diff --git a/frontend_tests/casper_lib/common.js b/frontend_tests/casper_lib/common.js
index 0e44d280ce..4f2e907669 100644
--- a/frontend_tests/casper_lib/common.js
+++ b/frontend_tests/casper_lib/common.js
@@ -205,7 +205,7 @@ exports.turn_off_press_enter_to_send = function () {
 exports.then_send_message = function (type, params) {
     casper.then(function () {
         casper.waitForSelector('#compose-send-button:enabled');
-        casper.waitForSelector('#new_message_content');
+        casper.waitForSelector('#compose-textarea');
     });
 
     casper.then(function () {
diff --git a/frontend_tests/casper_tests/08-edit.js b/frontend_tests/casper_tests/08-edit.js
index 11b04bbef7..dcdc5ef016 100644
--- a/frontend_tests/casper_tests/08-edit.js
+++ b/frontend_tests/casper_tests/08-edit.js
@@ -119,8 +119,8 @@ casper.then(function () {
 casper.then(function () {
     casper.waitUntilVisible('#compose', function () {
         casper.evaluate(function () {
-            $('#new_message_content').expectOne().focus();
-            $('#new_message_content').trigger($.Event('keydown', { which: 37 }));
+            $('#compose-textarea').expectOne().focus();
+            $('#compose-textarea').trigger($.Event('keydown', { which: 37 }));
         });
     });
 });
@@ -142,8 +142,8 @@ casper.then(function () {
 casper.then(function () {
     casper.waitUntilVisible('#compose', function () {
         casper.evaluate(function () {
-            $('#new_message_content').expectOne().focus().val('test');
-            $('#new_message_content').trigger($.Event('keydown', { which: 37 }));
+            $('#compose-textarea').expectOne().focus().val('test');
+            $('#compose-textarea').trigger($.Event('keydown', { which: 37 }));
         });
         casper.test.assertNotVisible('form.message_edit_form', "Last own message edit doesn't open if the compose box not empty");
     });
diff --git a/frontend_tests/casper_tests/11-mention.js b/frontend_tests/casper_tests/11-mention.js
index e2a28ed649..5d8c1220d5 100644
--- a/frontend_tests/casper_tests/11-mention.js
+++ b/frontend_tests/casper_tests/11-mention.js
@@ -13,7 +13,7 @@ casper.then(function () {
         subject: 'Test mention all',
     });
 });
-common.select_item_via_typeahead('#new_message_content', '@all', 'all');
+common.select_item_via_typeahead('#compose-textarea', '@all', 'all');
 
 casper.then(function () {
     common.turn_off_press_enter_to_send();
diff --git a/frontend_tests/node_tests/compose.js b/frontend_tests/node_tests/compose.js
index 11f09742ed..f87d113076 100644
--- a/frontend_tests/node_tests/compose.js
+++ b/frontend_tests/node_tests/compose.js
@@ -144,14 +144,14 @@ people.add(bob);
     $("#compose-send-button").prop('disabled', false);
     $("#compose-send-button").focus();
     $("#sending-indicator").hide();
-    $("#new_message_content").select(noop);
+    $("#compose-textarea").select(noop);
     assert(!compose.validate());
     assert(!$("#sending-indicator").visible());
     assert(!$("#compose-send-button").is_focused());
     assert.equal($("#compose-send-button").prop('disabled'), false);
     assert.equal($('#compose-error-msg').html(), i18n.t('You have nothing to send!'));
 
-    $("#new_message_content").val('foobarfoobar');
+    $("#compose-textarea").val('foobarfoobar');
     var zephyr_checked = false;
     $("#zephyr-mirror-error").is = function () {
         if (!zephyr_checked) {
@@ -259,8 +259,8 @@ people.add(bob);
 (function test_send_message_success() {
     blueslip.error = noop;
     blueslip.log = noop;
-    $("#new_message_content").val('foobarfoobar');
-    $("#new_message_content").blur();
+    $("#compose-textarea").val('foobarfoobar');
+    $("#compose-textarea").blur();
     $("#compose-send-status").show();
     $("#compose-send-button").attr('disabled', 'disabled');
     $("#sending-indicator").show();
@@ -274,8 +274,8 @@ people.add(bob);
 
     compose.send_message_success(1001, 12, false);
 
-    assert.equal($("#new_message_content").val(), '');
-    assert($("#new_message_content").is_focused());
+    assert.equal($("#compose-textarea").val(), '');
+    assert($("#compose-textarea").is_focused());
     assert(!$("#compose-send-status").visible());
     assert.equal($("#compose-send-button").prop('disabled'), false);
     assert(!$("#sending-indicator").visible());
@@ -345,9 +345,9 @@ people.add(bob);
 
         // Setting message content with a host server link and we will assert
         // later that this has been converted to a relative link.
-        $("#new_message_content").val('[foobar]' +
+        $("#compose-textarea").val('[foobar]' +
                                       '(https://foo.com/user_uploads/123456)');
-        $("#new_message_content").blur();
+        $("#compose-textarea").blur();
         $("#compose-send-status").show();
         $("#compose-send-button").attr('disabled', 'disabled');
         $("#sending-indicator").show();
@@ -361,8 +361,8 @@ people.add(bob);
             send_msg_ajax_post_called: 1,
         };
         assert.deepEqual(stub_state, state);
-        assert.equal($("#new_message_content").val(), '');
-        assert($("#new_message_content").is_focused());
+        assert.equal($("#compose-textarea").val(), '');
+        assert($("#compose-textarea").is_focused());
         assert(!$("#compose-send-status").visible());
         assert.equal($("#compose-send-button").prop('disabled'), false);
         assert(!$("#sending-indicator").visible());
@@ -441,12 +441,12 @@ people.add(bob);
 
     (function test_error_codepath_local_id_undefined() {
         stub_state = initialize_state_stub_dict();
-        $("#new_message_content").val('foobarfoobar');
-        $("#new_message_content").blur();
+        $("#compose-textarea").val('foobarfoobar');
+        $("#compose-textarea").blur();
         $("#compose-send-status").show();
         $("#compose-send-button").attr('disabled', 'disabled');
         $("#sending-indicator").show();
-        $("#new_message_content").select(noop);
+        $("#compose-textarea").select(noop);
         echo_error_msg_checked = false;
         xhr_error_msg_checked = false;
         server_error_triggered = false;
@@ -475,8 +475,8 @@ people.add(bob);
         assert.equal($("#compose-send-button").prop('disabled'), false);
         assert.equal($('#compose-error-msg').html(),
                        'Error sending message: Server says 408');
-        assert.equal($("#new_message_content").val(), 'foobarfoobar');
-        assert($("#new_message_content").is_focused());
+        assert.equal($("#compose-textarea").val(), 'foobarfoobar');
+        assert($("#compose-textarea").is_focused());
         assert($("#compose-send-status").visible());
         assert.equal($("#compose-send-button").prop('disabled'), false);
         assert(!$("#sending-indicator").visible());
@@ -485,8 +485,8 @@ people.add(bob);
 
 (function test_enter_with_preview_open() {
     // Test sending a message with content.
-    $("#new_message_content").val('message me');
-    $("#new_message_content").hide();
+    $("#compose-textarea").val('message me');
+    $("#compose-textarea").hide();
     $("#undo_markdown_preview").show();
     $("#preview_message_area").show();
     $("#markdown_preview").hide();
@@ -496,19 +496,19 @@ people.add(bob);
         send_message_called = true;
     };
     compose.enter_with_preview_open();
-    assert($("#new_message_content").visible());
+    assert($("#compose-textarea").visible());
     assert(!$("#undo_markdown_preview").visible());
     assert(!$("#preview_message_area").visible());
     assert($("#markdown_preview").visible());
     assert(send_message_called);
 
     page_params.enter_sends = false;
-    $("#new_message_content").blur();
+    $("#compose-textarea").blur();
     compose.enter_with_preview_open();
-    assert($("#new_message_content").is_focused());
+    assert($("#compose-textarea").is_focused());
 
     // Test sending a message without content.
-    $("#new_message_content").val('');
+    $("#compose-textarea").val('');
     $("#preview_message_area").show();
     $("#enter_sends").prop("checked", true);
     page_params.enter_sends = true;
@@ -525,8 +525,8 @@ people.add(bob);
         $("#compose-send-button").prop('disabled', false);
         $("#compose-send-button").focus();
         $("#sending-indicator").hide();
-        $("#new_message_content").select(noop);
-        $("#new_message_content").val('');
+        $("#compose-textarea").select(noop);
+        $("#compose-textarea").val('');
         var res = compose.finish();
         assert.equal(res, false);
         assert(!$("#compose_invite_users").visible());
@@ -537,11 +537,11 @@ people.add(bob);
     }());
 
     (function test_when_compose_validation_succeed() {
-        $("#new_message_content").hide();
+        $("#compose-textarea").hide();
         $("#undo_markdown_preview").show();
         $("#preview_message_area").show();
         $("#markdown_preview").hide();
-        $("#new_message_content").val('foobarfoobar');
+        $("#compose-textarea").val('foobarfoobar');
         compose_state.set_message_type('private');
         compose_state.recipient('bob@example.com');
         var compose_finished_event_checked = false;
@@ -556,7 +556,7 @@ people.add(bob);
             send_message_called = true;
         };
         assert(compose.finish());
-        assert($("#new_message_content").visible());
+        assert($("#compose-textarea").visible());
         assert(!$("#undo_markdown_preview").visible());
         assert(!$("#preview_message_area").visible());
         assert($("#markdown_preview").visible());
@@ -610,7 +610,7 @@ function test_raw_file_drop(raw_drop_func) {
             compose_actions_start_checked = true;
         },
     };
-    $("#new_message_content").val('Old content ');
+    $("#compose-textarea").val('Old content ');
     var compose_ui_autosize_textarea_checked = false;
     compose_ui.autosize_textarea = function () {
         compose_ui_autosize_textarea_checked = true;
@@ -620,7 +620,7 @@ function test_raw_file_drop(raw_drop_func) {
     raw_drop_func('new contents');
 
     assert(compose_actions_start_checked);
-    assert.equal($("#new_message_content").val(), 'Old content new contents');
+    assert.equal($("#compose-textarea").val(), 'Old content new contents');
     assert(compose_ui_autosize_textarea_checked);
 }
 
@@ -631,7 +631,7 @@ function test_raw_file_drop(raw_drop_func) {
 
     var resize_watch_manual_resize_checked = false;
     resize.watch_manual_resize = function (elem) {
-        assert.equal('#new_message_content', elem);
+        assert.equal('#compose-textarea', elem);
         resize_watch_manual_resize_checked = true;
     };
     global.window = {
@@ -1138,31 +1138,31 @@ function test_with_mock_socket(test_params) {
     (function test_video_link_compose_clicked() {
         // Hackishly pretend caret is the same as val, since we don't
         // have a cursor anyway.
-        $('#new_message_content').caret = function (x) {
-            $('#new_message_content').val(x);
+        $('#compose-textarea').caret = function (x) {
+            $('#compose-textarea').val(x);
         };
 
         var handler = $("#compose").get_on_handler("click", "#video_link");
-        assert.equal($('#new_message_content').val(), '');
+        assert.equal($('#compose-textarea').val(), '');
 
         handler(event);
 
         // video link ids consist of 15 random digits
         var video_link_regex = /\[Click to join video call\]\(https:\/\/meet.jit.si\/\d{15}\)/;
-        assert(video_link_regex.test($('#new_message_content').val()));
+        assert(video_link_regex.test($('#compose-textarea').val()));
     }());
 
     (function test_markdown_preview_compose_clicked() {
         // Tests setup
         function setup_visibilities() {
-            $("#new_message_content").show();
+            $("#compose-textarea").show();
             $("#markdown_preview").show();
             $("#undo_markdown_preview").hide();
             $("#preview_message_area").hide();
         }
 
         function assert_visibilities() {
-            assert(!$("#new_message_content").visible());
+            assert(!$("#compose-textarea").visible());
             assert(!$("#markdown_preview").visible());
             assert($("#undo_markdown_preview").visible());
             assert($("#preview_message_area").visible());
@@ -1219,7 +1219,7 @@ function test_with_mock_socket(test_params) {
                         .get_on_handler("click", "#markdown_preview");
 
         // Tests start here
-        $("#new_message_content").val('');
+        $("#compose-textarea").val('');
         setup_visibilities();
 
         handler(event);
@@ -1229,7 +1229,7 @@ function test_with_mock_socket(test_params) {
         assert_visibilities();
 
         var make_indicator_called = false;
-        $("#new_message_content").val('```foobarfoobar```');
+        $("#compose-textarea").val('```foobarfoobar```');
         setup_visibilities();
         setup_mock_markdown_contains_backend_only_syntax('```foobarfoobar```', true);
         loading.make_indicator = function (spinner) {
@@ -1244,7 +1244,7 @@ function test_with_mock_socket(test_params) {
         assert_visibilities();
 
         var apply_markdown_called = false;
-        $("#new_message_content").val('foobarfoobar');
+        $("#compose-textarea").val('foobarfoobar');
         setup_visibilities();
         setup_mock_markdown_contains_backend_only_syntax('foobarfoobar', false);
         mock_channel_post('foobarfoobar');
@@ -1266,14 +1266,14 @@ function test_with_mock_socket(test_params) {
         var handler = $("#compose")
                         .get_on_handler("click", "#undo_markdown_preview");
 
-        $("#new_message_content").hide();
+        $("#compose-textarea").hide();
         $("#undo_markdown_preview").show();
         $("#preview_message_area").show();
         $("#markdown_preview").hide();
 
         handler(event);
 
-        assert($("#new_message_content").visible());
+        assert($("#compose-textarea").visible());
         assert(!$("#undo_markdown_preview").visible());
         assert(!$("#preview_message_area").visible());
         assert($("#markdown_preview").visible());
@@ -1292,7 +1292,7 @@ function test_with_mock_socket(test_params) {
     var page = {
         '#stream': 'social',
         '#subject': 'lunch',
-        '#new_message_content': 'burrito',
+        '#compose-textarea': 'burrito',
         '#private_message_recipient': 'alice@example.com,    bob@example.com',
     };
 
diff --git a/frontend_tests/node_tests/compose_actions.js b/frontend_tests/node_tests/compose_actions.js
index cf7841d289..0809c5837b 100644
--- a/frontend_tests/node_tests/compose_actions.js
+++ b/frontend_tests/node_tests/compose_actions.js
@@ -119,14 +119,14 @@ function assert_hidden(sel) {
         content: 'hello',
     };
 
-    $('#new_message_content').trigger = noop;
+    $('#compose-textarea').trigger = noop;
     start('private', opts);
 
     assert_hidden('#stream-message');
     assert_visible('#private-message');
 
     assert.equal($('#private_message_recipient').val(), 'foo@example.com');
-    assert.equal($('#new_message_content').val(), 'hello');
+    assert.equal($('#compose-textarea').val(), 'hello');
     assert.equal(compose_state.get_message_type(), 'private');
     assert(compose_state.composing());
 
@@ -191,20 +191,20 @@ function assert_hidden(sel) {
 
     reply_with_mention(opts);
     assert.equal($('#stream').val(), 'devel');
-    assert.equal($('#new_message_content').val(), '@**Bob Roberts** ');
+    assert.equal($('#compose-textarea').val(), '@**Bob Roberts** ');
     assert(compose_state.has_message_content());
 }());
 
 (function test_get_focus_area() {
     assert.equal(get_focus_area('private', {}), 'private_message_recipient');
     assert.equal(get_focus_area('private', {
-        private_message_recipient: 'bob@example.com'}), 'new_message_content');
+        private_message_recipient: 'bob@example.com'}), 'compose-textarea');
     assert.equal(get_focus_area('stream', {}), 'stream');
     assert.equal(get_focus_area('stream', {stream: 'fun'}),
                  'subject');
     assert.equal(get_focus_area('stream', {stream: 'fun',
                                            subject: 'more'}),
-                 'new_message_content');
+                 'compose-textarea');
     assert.equal(get_focus_area('stream', {stream: 'fun',
                                            subject: 'more',
                                            trigger: 'new topic button'}),
@@ -212,22 +212,22 @@ function assert_hidden(sel) {
 }());
 
 (function test_focus_in_empty_compose() {
-    $('#new_message_content').is = function (attr) {
+    $('#compose-textarea').is = function (attr) {
         assert.equal(attr, ':focus');
-        return $('#new_message_content').is_focused;
+        return $('#compose-textarea').is_focused;
     };
 
     compose_state.composing = return_true;
-    $('#new_message_content').val('');
-    $('#new_message_content').focus();
+    $('#compose-textarea').val('');
+    $('#compose-textarea').focus();
     assert(compose_state.focus_in_empty_compose());
 
     compose_state.composing = return_false;
     assert(!compose_state.focus_in_empty_compose());
 
-    $('#new_message_content').val('foo');
+    $('#compose-textarea').val('foo');
     assert(!compose_state.focus_in_empty_compose());
 
-    $('#new_message_content').blur();
+    $('#compose-textarea').blur();
     assert(!compose_state.focus_in_empty_compose());
 }());
diff --git a/frontend_tests/node_tests/composebox_typeahead.js b/frontend_tests/node_tests/composebox_typeahead.js
index 64514dc272..00faea9e04 100644
--- a/frontend_tests/node_tests/composebox_typeahead.js
+++ b/frontend_tests/node_tests/composebox_typeahead.js
@@ -510,8 +510,8 @@ global.user_groups.add(backend);
         pm_recipient_typeahead_called = true;
     };
 
-    var new_message_content_typeahead_called = false;
-    $('#new_message_content').typeahead = function (options) {
+    var compose_textarea_typeahead_called = false;
+    $('#compose-textarea').typeahead = function (options) {
         // options.source()
         //
         // For now we only test that compose_contents_begins_typeahead has been
@@ -603,7 +603,7 @@ global.user_groups.add(backend);
         fake_this = { completing: 'non-existing-completion' };
         assert.equal(options.sorter.call(fake_this), undefined);
 
-        new_message_content_typeahead_called = true;
+        compose_textarea_typeahead_called = true;
     };
 
     var pm_recipient_blur_called = false;
@@ -652,7 +652,7 @@ global.user_groups.add(backend);
     $('#subject').data = stub_typeahead_hidden;
     $('#stream').data = stub_typeahead_hidden;
     $('#private_message_recipient').data = stub_typeahead_hidden;
-    $('#new_message_content').data = stub_typeahead_hidden;
+    $('#compose-textarea').data = stub_typeahead_hidden;
     $('form#send_message_form').keydown(event);
 
     event.keyCode = undefined;
@@ -660,16 +660,16 @@ global.user_groups.add(backend);
     event.shiftKey = false;
     event.target.id = 'subject';
     $('form#send_message_form').keydown(event);
-    event.target.id = 'new_message_content';
+    event.target.id = 'compose-textarea';
     $('form#send_message_form').keydown(event);
     event.target.id = 'some_non_existing_id';
     $('form#send_message_form').keydown(event);
 
 
-    // Setup jquery functions used in new_message_content enter
+    // Setup jquery functions used in compose_textarea enter
     // handler.
     var range_length = 0;
-    $('#new_message_content').range = function () {
+    $('#compose-textarea').range = function () {
         return {
             length: range_length,
             range: noop,
@@ -677,12 +677,12 @@ global.user_groups.add(backend);
             end: 0 + range_length,
         };
     };
-    $('#new_message_content').caret = noop;
+    $('#compose-textarea').caret = noop;
 
     event.keyCode = 13;
     event.target.id = 'subject';
     $('form#send_message_form').keydown(event);
-    event.target.id = 'new_message_content';
+    event.target.id = 'compose-textarea';
     page_params.enter_sends = false;
     event.metaKey = true;
     var compose_finish_called = false;
@@ -776,7 +776,7 @@ global.user_groups.add(backend);
     assert(pm_recipient_typeahead_called);
     assert(pm_recipient_blur_called);
     assert(channel_post_called);
-    assert(new_message_content_typeahead_called);
+    assert(compose_textarea_typeahead_called);
     assert(focus_handler_called);
     assert(stream_one_called);
 }());
diff --git a/frontend_tests/node_tests/drafts.js b/frontend_tests/node_tests/drafts.js
index bdd4dfd1b4..014512ffda 100644
--- a/frontend_tests/node_tests/drafts.js
+++ b/frontend_tests/node_tests/drafts.js
@@ -129,7 +129,7 @@ var draft_2 = {
 }());
 
 (function test_initialize() {
-    var message_content = $("#new_message_content");
+    var message_content = $("#compose-textarea");
     message_content.focusout = function (f) {
         assert.equal(f, drafts.update_draft);
         f();
diff --git a/frontend_tests/node_tests/upload.js b/frontend_tests/node_tests/upload.js
index 6c5fa26322..f19043ffa2 100644
--- a/frontend_tests/node_tests/upload.js
+++ b/frontend_tests/node_tests/upload.js
@@ -107,7 +107,7 @@ zrequire('upload');
         var compose_actions_start_checked = false;
 
         function setup() {
-            $("#new_message_content").val('');
+            $("#compose-textarea").val('');
             compose_ui.autosize_textarea = function () {
                 compose_ui_autosize_textarea_checked = true;
             };
@@ -128,7 +128,7 @@ zrequire('upload');
         }
 
         function assert_side_effects() {
-            assert.equal($("#new_message_content").val(), textbox_val);
+            assert.equal($("#compose-textarea").val(), textbox_val);
             if (response.uri) {
                 assert(compose_actions_start_checked);
                 assert(compose_ui_autosize_textarea_checked);
diff --git a/static/js/click_handlers.js b/static/js/click_handlers.js
index 6dcbd73f7d..75832050c4 100644
--- a/static/js/click_handlers.js
+++ b/static/js/click_handlers.js
@@ -730,7 +730,7 @@ $(function () {
         if (compose_state.composing()) {
             if ($(e.target).is("a")) {
                 // Refocus compose message text box if link is clicked
-                $("#new_message_content").focus();
+                $("#compose-textarea").focus();
             } else if (!$(e.target).closest(".overlay").length &&
             !window.getSelection().toString() &&
             !$(e.target).closest('.popover-content').length) {
diff --git a/static/js/compose.js b/static/js/compose.js
index ad62672de5..4b67e4ba1b 100644
--- a/static/js/compose.js
+++ b/static/js/compose.js
@@ -60,7 +60,7 @@ exports.reset_user_acknowledged_all_everyone_flag = function () {
 };
 
 exports.clear_preview_area = function () {
-    $("#new_message_content").show();
+    $("#compose-textarea").show();
     $("#undo_markdown_preview").hide();
     $("#preview_message_area").hide();
     $("#preview_content").empty();
@@ -185,7 +185,7 @@ function send_message_socket(request, success, error) {
 }
 
 function clear_compose_box() {
-    $("#new_message_content").val('').focus();
+    $("#compose-textarea").val('').focus();
     drafts.delete_draft_after_send();
     compose_ui.autosize_textarea();
     $("#compose-send-status").hide(0);
@@ -266,7 +266,7 @@ exports.send_message = function send_message(request) {
         // If we're not local echo'ing messages, or if this message was not
         // locally echoed, show error in compose box
         if (!locally_echoed) {
-            compose_error(response, $('#new_message_content'));
+            compose_error(response, $('#compose-textarea'));
             return;
         }
 
@@ -288,7 +288,7 @@ exports.enter_with_preview_open = function () {
         exports.finish();
     } else {
         // Otherwise, we return to the compose box and focus it
-        $("#new_message_content").focus();
+        $("#compose-textarea").focus();
     }
 };
 
@@ -469,7 +469,7 @@ exports.validate = function () {
     $("#sending-indicator").show();
 
     if (/^\s*$/.test(compose_state.message_content())) {
-        compose_error(i18n.t("You have nothing to send!"), $("#new_message_content"));
+        compose_error(i18n.t("You have nothing to send!"), $("#compose-textarea"));
         return false;
     }
 
@@ -493,7 +493,7 @@ exports.initialize = function () {
        compose.finish();
     });
 
-    resize.watch_manual_resize("#new_message_content");
+    resize.watch_manual_resize("#compose-textarea");
 
     // Run a feature test and decide whether to display
     // the "Attach files" button
@@ -702,8 +702,8 @@ exports.initialize = function () {
 
     $("#compose").on("click", "#markdown_preview", function (e) {
         e.preventDefault();
-        var content = $("#new_message_content").val();
-        $("#new_message_content").hide();
+        var content = $("#compose-textarea").val();
+        $("#compose-textarea").hide();
         $("#markdown_preview").hide();
         $("#undo_markdown_preview").show();
         $("#preview_message_area").show();
@@ -757,7 +757,7 @@ exports.initialize = function () {
         var options = {
             // Required. Called when a user selects an item in the Chooser.
             success: function (files) {
-                var textbox = $("#new_message_content");
+                var textbox = $("#compose-textarea");
                 var links = _.map(files, function (file) { return '[' + file.name + '](' + file.link +')'; })
                              .join(' ') + ' ';
                 textbox.val(textbox.val() + links);
diff --git a/static/js/compose_actions.js b/static/js/compose_actions.js
index d1a9614e6b..1ddcdf6979 100644
--- a/static/js/compose_actions.js
+++ b/static/js/compose_actions.js
@@ -38,7 +38,7 @@ function get_focus_area(msg_type, opts) {
         if (opts.trigger === "new topic button") {
             return 'subject';
         }
-        return 'new_message_content';
+        return 'compose-textarea';
     }
 
     if (msg_type === 'stream') {
@@ -96,13 +96,13 @@ function clear_box() {
     compose.reset_user_acknowledged_all_everyone_flag();
 
     exports.clear_textarea();
-    $("#new_message_content").removeData("draft-id");
+    $("#compose-textarea").removeData("draft-id");
     compose_ui.autosize_textarea();
     $("#compose-send-status").hide(0);
 }
 
 exports.autosize_message_content = function () {
-    $("#new_message_content").autosize();
+    $("#compose-textarea").autosize();
 };
 
 exports.expand_compose_box = function () {
@@ -221,7 +221,7 @@ exports.start = function (msg_type, opts) {
 };
 
 exports.cancel = function () {
-    $("#new_message_content").height(40 + "px");
+    $("#compose-textarea").height(40 + "px");
 
     if (page_params.narrow !== undefined) {
         // Never close the compose box in narrow embedded windows, but
@@ -307,7 +307,7 @@ exports.reply_with_mention = function (opts) {
     exports.respond_to_message(opts);
     var message = current_msg_list.selected_message();
     var mention = '@**' + message.sender_full_name + '**';
-    $('#new_message_content').val(mention + ' ');
+    $('#compose-textarea').val(mention + ' ');
 };
 
 exports.on_topic_narrow = function () {
@@ -349,7 +349,7 @@ exports.on_topic_narrow = function () {
     // See #3300 for context--a couple users specifically asked
     // for this convenience.
     compose_state.subject(narrow_state.topic());
-    $('#new_message_content').focus().select();
+    $('#compose-textarea').focus().select();
 };
 
 exports.on_narrow = function () {
diff --git a/static/js/compose_state.js b/static/js/compose_state.js
index 40561c4ce5..7a196f8d48 100644
--- a/static/js/compose_state.js
+++ b/static/js/compose_state.js
@@ -22,7 +22,7 @@ exports.focus_in_empty_compose = function () {
     return (
         exports.composing() &&
         exports.message_content() === "" &&
-        $('#new_message_content').is(':focus'));
+        $('#compose-textarea').is(':focus'));
 };
 
 function get_or_set(fieldname, keep_leading_whitespace) {
@@ -42,9 +42,9 @@ function get_or_set(fieldname, keep_leading_whitespace) {
 // TODO: Break out setters and getter into their own functions.
 exports.stream_name     = get_or_set('stream');
 exports.subject         = get_or_set('subject');
-// We can't trim leading whitespace in `new_message_content` because
+// We can't trim leading whitespace in `compose_textarea` because
 // of the indented syntax for multi-line code blocks.
-exports.message_content = get_or_set('new_message_content', true);
+exports.message_content = get_or_set('compose-textarea', true);
 exports.recipient       = get_or_set('private_message_recipient');
 
 exports.has_message_content = function () {
diff --git a/static/js/compose_ui.js b/static/js/compose_ui.js
index 3d7b2955ff..71bfddbee2 100644
--- a/static/js/compose_ui.js
+++ b/static/js/compose_ui.js
@@ -3,7 +3,7 @@ var compose_ui = (function () {
 var exports = {};
 
 exports.autosize_textarea = function () {
-    $("#new_message_content").trigger("autosize.resize");
+    $("#compose-textarea").trigger("autosize.resize");
 };
 
 exports.smart_insert = function (textarea, syntax) {
@@ -38,7 +38,7 @@ exports.insert_syntax_and_focus = function (syntax) {
     // Generic helper for inserting syntax into the main compose box
     // where the cursor was and focusing the area.  Mostly a thin
     // wrapper around smart_insert.
-    var textarea = $('#new_message_content');
+    var textarea = $('#compose-textarea');
     exports.smart_insert(textarea, syntax);
 };
 
diff --git a/static/js/composebox_typeahead.js b/static/js/composebox_typeahead.js
index aca91b8f17..e57cc7b7e2 100644
--- a/static/js/composebox_typeahead.js
+++ b/static/js/composebox_typeahead.js
@@ -95,8 +95,8 @@ function handle_keydown(e) {
             e.preventDefault();
         }
 
-        // In the new_message_content box, preventDefault() for tab but not for enter
-        if (e.target.id === "new_message_content" && code !== 13) {
+        // In the compose_textarea box, preventDefault() for tab but not for enter
+        if (e.target.id === 'compose-textarea' && code !== 13) {
             e.preventDefault();
         }
 
@@ -106,10 +106,10 @@ function handle_keydown(e) {
             if (code === 13) {
                 e.preventDefault();
             }
-            nextFocus = "new_message_content";
+            nextFocus = 'compose-textarea';
         } else if (e.target.id === "private_message_recipient") {
-            nextFocus = "new_message_content";
-        } else if (e.target.id === "new_message_content") {
+            nextFocus = 'compose-textarea';
+        } else if (e.target.id === 'compose-textarea') {
             if (code === 13) {
                 nextFocus = false;
             } else {
@@ -123,7 +123,7 @@ function handle_keydown(e) {
         if (!($("#subject").data().typeahead.shown ||
               $("#stream").data().typeahead.shown ||
               $("#private_message_recipient").data().typeahead.shown ||
-              $("#new_message_content").data().typeahead.shown)) {
+              $("#compose-textarea").data().typeahead.shown)) {
 
             // If no typeaheads are shown and the user is tabbing from the message content box,
             // then there's no need to wait and we can change the focus right away.
@@ -137,7 +137,7 @@ function handle_keydown(e) {
                 nextFocus = false;
             }
 
-            if (e.target.id === "new_message_content" && code === 13) {
+            if (e.target.id === 'compose-textarea' && code === 13) {
                 var has_non_shift_modifier_key = e.ctrlKey || e.metaKey || e.altKey;
                 var has_modifier_key = e.shiftKey || has_non_shift_modifier_key;
                 var this_enter_sends;
@@ -176,7 +176,7 @@ function handle_keydown(e) {
                 //
                 // We do this using caret and range from jquery-caret.
                 if (has_non_shift_modifier_key) {
-                    var textarea = $("#new_message_content");
+                    var textarea = $("#compose-textarea");
 
                     // To properly emulate browser "enter", if the
                     // user had selected something in the compose box,
@@ -546,7 +546,7 @@ exports.initialize = function () {
 
         // Refocus in the content box so you can continue typing or
         // press Enter to send.
-        $("#new_message_content").focus();
+        $("#compose-textarea").focus();
 
         return channel.post({
             url: '/json/users/me/enter-sends',
@@ -637,7 +637,7 @@ exports.initialize = function () {
         stopAdvance: true, // Do not advance to the next field on a tab or enter
     });
 
-    exports.initialize_compose_typeahead("#new_message_content");
+    exports.initialize_compose_typeahead("#compose-textarea");
 
     $("#private_message_recipient").blur(function () {
         var val = $(this).val();
diff --git a/static/js/copy_and_paste.js b/static/js/copy_and_paste.js
index b35961425b..9a38474213 100644
--- a/static/js/copy_and_paste.js
+++ b/static/js/copy_and_paste.js
@@ -182,7 +182,7 @@ exports.paste_handler = function (event) {
 
 $(function () {
     $(document).on('copy', copy_handler);
-    $("#new_message_content").bind('paste', exports.paste_handler);
+    $("#compose-textarea").bind('paste', exports.paste_handler);
 });
 
 return exports;
diff --git a/static/js/drafts.js b/static/js/drafts.js
index 759656b3f5..dc8fd72dd0 100644
--- a/static/js/drafts.js
+++ b/static/js/drafts.js
@@ -88,7 +88,7 @@ exports.snapshot_message = function () {
 
 exports.update_draft = function () {
     var draft = drafts.snapshot_message();
-    var draft_id = $("#new_message_content").data("draft-id");
+    var draft_id = $("#compose-textarea").data("draft-id");
 
     if (draft_id !== undefined) {
         if (draft !== undefined) {
@@ -99,17 +99,17 @@ exports.update_draft = function () {
     } else {
         if (draft !== undefined) {
             var new_draft_id = draft_model.addDraft(draft);
-            $("#new_message_content").data("draft-id", new_draft_id);
+            $("#compose-textarea").data("draft-id", new_draft_id);
         }
     }
 };
 
 exports.delete_draft_after_send = function () {
-    var draft_id = $("#new_message_content").data("draft-id");
+    var draft_id = $("#compose-textarea").data("draft-id");
     if (draft_id) {
         draft_model.deleteDraft(draft_id);
     }
-    $("#new_message_content").removeData("draft-id");
+    $("#compose-textarea").removeData("draft-id");
 };
 
 exports.restore_draft = function (draft_id) {
@@ -148,7 +148,7 @@ exports.restore_draft = function (draft_id) {
     }
     compose_actions.start(draft_copy.type, draft_copy);
     compose_ui.autosize_textarea();
-    $("#new_message_content").data("draft-id", draft_id);
+    $("#compose-textarea").data("draft-id", draft_id);
 };
 
 exports.setup_page = function (callback) {
@@ -403,7 +403,7 @@ exports.initialize = function () {
         exports.update_draft();
     });
 
-    $("#new_message_content").focusout(exports.update_draft);
+    $("#compose-textarea").focusout(exports.update_draft);
 };
 
 return exports;
diff --git a/static/js/hotkey.js b/static/js/hotkey.js
index 19f710aaa2..03582d8758 100644
--- a/static/js/hotkey.js
+++ b/static/js/hotkey.js
@@ -531,11 +531,11 @@ exports.process_hotkey = function (e, hotkey) {
             compose_actions.cancel();
             // don't return, as we still want it to be picked up by the code below
         } else if (event_name === "page_up") {
-            $("#new_message_content").caret(0);
+            $("#compose-textarea").caret(0);
             return true;
         } else if (event_name === "page_down") {
             // so that it always goes to the end of the compose box.
-            $("#new_message_content").caret(Infinity);
+            $("#compose-textarea").caret(Infinity);
             return true;
         } else {
             // Let the browser handle the key normally.
diff --git a/static/js/popovers.js b/static/js/popovers.js
index 722d8ff010..ac3c4df871 100644
--- a/static/js/popovers.js
+++ b/static/js/popovers.js
@@ -390,7 +390,7 @@ exports.register_click_handlers = function () {
         var user_id = $(e.target).parents('ul').attr('data-user-id');
         compose_actions.start('stream', {trigger: 'sidebar user actions'});
         var name = people.get_person_from_user_id(user_id).full_name;
-        var textarea = $("#new_message_content");
+        var textarea = $("#compose-textarea");
         textarea.val('@**' + name + '** ');
         popovers.hide_user_sidebar_popover();
         e.stopPropagation();
@@ -419,7 +419,7 @@ exports.register_click_handlers = function () {
         compose_actions.respond_to_message({trigger: 'user sidebar popover'});
         var user_id = $(e.target).parents('ul').attr('data-user-id');
         var name = people.get_person_from_user_id(user_id).full_name;
-        var textarea = $("#new_message_content");
+        var textarea = $("#compose-textarea");
         textarea.val('@**' + name + '** ');
         popovers.hide_message_info_popover();
         e.stopPropagation();
@@ -480,7 +480,7 @@ exports.register_click_handlers = function () {
     });
 
     $('body').on('click', '.respond_button', function (e) {
-        var textarea = $("#new_message_content");
+        var textarea = $("#compose-textarea");
         var msgid = $(e.currentTarget).data("message-id");
 
         compose_actions.respond_to_message({trigger: 'popover respond'});
@@ -493,7 +493,7 @@ exports.register_click_handlers = function () {
                 } else {
                     textarea.val(textarea.val() + "\n```quote\n" + data.raw_content +"\n```\n");
                 }
-                $("#new_message_content").trigger("autosize.resize");
+                $("#compose-textarea").trigger("autosize.resize");
             },
         });
         popovers.hide_actions_popover();
diff --git a/static/js/settings_org.js b/static/js/settings_org.js
index 9cb5228cf1..0d809d29b1 100644
--- a/static/js/settings_org.js
+++ b/static/js/settings_org.js
@@ -404,7 +404,7 @@ function _set_up() {
         // grab the first alert available and use it for the status.
         var status = $("#admin-realm-notifications-stream-status");
 
-        var new_message_content_edit_limit_minutes = $("#id_realm_message_content_edit_limit_minutes").val();
+        var compose_textarea_edit_limit_minutes = $("#id_realm_message_content_edit_limit_minutes").val();
         var new_allow_message_editing = $("#id_realm_allow_message_editing").prop("checked");
 
         // If allow_message_editing is unchecked, message_content_edit_limit_minutes
@@ -412,11 +412,11 @@ function _set_up() {
         // message_content_edit_limit_minutes is poorly formed, we set the latter to
         // a default value to prevent the server from returning an error.
         if (!new_allow_message_editing) {
-            if ((parseInt(new_message_content_edit_limit_minutes, 10).toString() !==
-                 new_message_content_edit_limit_minutes) ||
-                new_message_content_edit_limit_minutes < 0) {
+            if ((parseInt(compose_textarea_edit_limit_minutes, 10).toString() !==
+                 compose_textarea_edit_limit_minutes) ||
+                compose_textarea_edit_limit_minutes < 0) {
             // Realm.DEFAULT_MESSAGE_CONTENT_EDIT_LIMIT_SECONDS / 60
-            new_message_content_edit_limit_minutes = 10;
+            compose_textarea_edit_limit_minutes = 10;
             }
         }
 
@@ -425,7 +425,7 @@ function _set_up() {
         data = populate_data_for_request({
             allow_message_editing: JSON.stringify(new_allow_message_editing),
             message_content_edit_limit_seconds:
-                JSON.stringify(parseInt(new_message_content_edit_limit_minutes, 10) * 60),
+                JSON.stringify(parseInt(compose_textarea_edit_limit_minutes, 10) * 60),
         }, 'settings');
 
         channel.patch({
diff --git a/static/js/typing.js b/static/js/typing.js
index 5faec40370..f364566d91 100644
--- a/static/js/typing.js
+++ b/static/js/typing.js
@@ -81,7 +81,7 @@ var worker = {
     notify_server_stop: notify_server_stop,
 };
 
-$(document).on('input', '#new_message_content', function () {
+$(document).on('input', '#compose-textarea', function () {
     // If our previous state was no typing notification, send a
     // start-typing notice immediately.
     typing_status.handle_text_input(worker);
diff --git a/static/js/ui.js b/static/js/ui.js
index 5247b1bc7e..ec8200bd46 100644
--- a/static/js/ui.js
+++ b/static/js/ui.js
@@ -250,7 +250,7 @@ $(function () {
         scroll_finish();
     }));
 
-    $('#new_message_content').blur(function () {
+    $('#compose-textarea').blur(function () {
         saved_compose_cursor = $(this).caret();
     });
 
@@ -262,7 +262,7 @@ $(function () {
 });
 
 exports.restore_compose_cursor = function () {
-    $('#new_message_content')
+    $('#compose-textarea')
         .focus()
         .caret(saved_compose_cursor);
 };
@@ -272,7 +272,7 @@ $(function () {
         // Disable "spellchecking" in our desktop app. The "spellchecking"
         // in our Mac app is actually autocorrect, and frustrates our
         // users.
-        $("#new_message_content").attr('spellcheck', 'false');
+        $("#compose-textarea").attr('spellcheck', 'false');
         // Modify the zephyr mirroring error message in our desktop
         // app, since it doesn't work from the desktop version.
         $("#webathena_login_menu").hide();
diff --git a/static/js/upload.js b/static/js/upload.js
index 8565503fd9..d43c694a55 100644
--- a/static/js/upload.js
+++ b/static/js/upload.js
@@ -74,7 +74,7 @@ exports.uploadFinished = function (i, file, response) {
     if (response.uri === undefined) {
         return;
     }
-    var textbox = $("#new_message_content");
+    var textbox = $("#compose-textarea");
     var split_uri = response.uri.split("/");
     var filename = split_uri[split_uri.length - 1];
     // Urgh, yet another hack to make sure we're "composing"
@@ -120,7 +120,7 @@ exports.initialize = function () {
         error: exports.uploadError,
         uploadFinished: exports.uploadFinished,
         rawDrop: function (contents) {
-            var textbox = $("#new_message_content");
+            var textbox = $("#compose-textarea");
             if (!compose_state.composing()) {
                 compose_actions.start('stream');
             }
diff --git a/templates/zerver/compose.html b/templates/zerver/compose.html
index a580ff2bb3..ddb63dacfb 100644
--- a/templates/zerver/compose.html
+++ b/templates/zerver/compose.html
@@ -78,7 +78,7 @@
             </tr>
             <tr>
               <td class="messagebox" colspan="2">
-                <textarea class="new_message_textarea" name="content" id="new_message_content"
+                <textarea class="new_message_textarea" name="content" id='compose-textarea'
                           value="" placeholder="{{ _('Compose your message here...') }}" tabindex="0" maxlength="10000" aria-label="{{ _('Compose your message here...') }}"></textarea>
                 <div class="scrolling_list" id="preview_message_area" style="display:none;">
                   <div id="markdown_preview_spinner"></div>