diff --git a/frontend_tests/node_tests/activity.js b/frontend_tests/node_tests/activity.js
index cc0f1d7900..7b68ad51b2 100644
--- a/frontend_tests/node_tests/activity.js
+++ b/frontend_tests/node_tests/activity.js
@@ -522,7 +522,7 @@ $('.user-list-filter').is = function (sel) {
 
 (function test_clear_search() {
     $('.user-list-filter').val('somevalue');
-    $('#clear_search_people_button').removeAttr('disabled');
+    $('#clear_search_people_button').prop('disabled', false);
     $('.user-list-filter').focus();
     activity.clear_search();
     assert.equal($('.user-list-filter').val(), '');
@@ -536,7 +536,7 @@ $('.user-list-filter').is = function (sel) {
     $('#clear_search_people_button').attr('disabled', 'disabled');
     activity.blur_search();
     assert.equal($('.user-list-filter').is_focused(), false);
-    assert.equal($('#clear_search_people_button').attr('disabled'), undefined);
+    assert.equal($('#clear_search_people_button').prop('disabled'), false);
     $('.user-list-filter').val('');
     activity.blur_search();
     assert.equal($('#clear_search_people_button').attr('disabled'), 'disabled');
@@ -553,14 +553,14 @@ $('.user-list-filter').is = function (sel) {
     activity.escape_search();
     assert.equal($('.user-list-filter').is_focused(), false);
     $('.user-list-filter').val('foobar');
-    $('#clear_search_people_button').removeAttr('disabled');
+    $('#clear_search_people_button').prop('disabled', false);
     activity.escape_search();
     assert.equal($('.user-list-filter').val(), '');
     assert.equal($('#clear_search_people_button').attr('disabled'), 'disabled');
     $('.user-list-filter').focus();
     $('.user-list-filter').val('foobar');
     activity.escape_search();
-    assert.equal($('#clear_search_people_button').attr('disabled'), undefined);
+    assert.equal($('#clear_search_people_button').prop('disabled'), false);
 }());
 
 (function test_searching() {
diff --git a/frontend_tests/node_tests/compose.js b/frontend_tests/node_tests/compose.js
index ed22bb9ada..218869d9e6 100644
--- a/frontend_tests/node_tests/compose.js
+++ b/frontend_tests/node_tests/compose.js
@@ -138,14 +138,14 @@ people.add(bob);
 }());
 
 (function test_validate() {
-    $("#compose-send-button").removeAttr('disabled');
+    $("#compose-send-button").prop('disabled', false);
     $("#compose-send-button").focus();
     $("#sending-indicator").hide();
     $("#new_message_content").select(noop);
     assert(!compose.validate());
     assert(!$("#sending-indicator").visible());
     assert(!$("#compose-send-button").is_focused());
-    assert.equal($("#compose-send-button").attr('disabled'), undefined);
+    assert.equal($("#compose-send-button").prop('disabled'), false);
     assert.equal($('#error-msg').html(), i18n.t('You have nothing to send!'));
 
     $("#new_message_content").val('foobarfoobar');
@@ -247,7 +247,7 @@ people.add(bob);
     };
     compose_state.message_content('Hey @all');
     assert(!compose.validate());
-    assert.equal($("#compose-send-button").attr('disabled'), undefined);
+    assert.equal($("#compose-send-button").prop('disabled'), false);
     assert(!$("#send-status").visible());
     assert.equal(compose_content, 'compose_all_everyone_stub');
     assert($("#compose-all-everyone").visible());
@@ -286,7 +286,7 @@ people.add(bob);
     assert.equal($("#new_message_content").val(), '');
     assert($("#new_message_content").is_focused());
     assert(!$("#send-status").visible());
-    assert.equal($("#compose-send-button").attr('disabled'), undefined);
+    assert.equal($("#compose-send-button").prop('disabled'), false);
     assert(!$("#sending-indicator").visible());
     assert.equal(_.keys(compose.send_times_data).length, 1);
     assert.equal(compose.send_times_data[12].start.getTime(), new Date(test_date).getTime());
@@ -418,7 +418,7 @@ people.add(bob);
         assert.equal($("#new_message_content").val(), '');
         assert($("#new_message_content").is_focused());
         assert(!$("#send-status").visible());
-        assert.equal($("#compose-send-button").attr('disabled'), undefined);
+        assert.equal($("#compose-send-button").prop('disabled'), false);
         assert(!$("#sending-indicator").visible());
     }());
 
@@ -528,13 +528,13 @@ people.add(bob);
         assert(!reload_initiate_triggered);
         assert(xhr_error_msg_checked);
         assert(!echo_error_msg_checked);
-        assert.equal($("#compose-send-button").attr('disabled'), undefined);
+        assert.equal($("#compose-send-button").prop('disabled'), false);
         assert.equal($('#error-msg').html(),
                        'Error sending message: Server says 408');
         assert.equal($("#new_message_content").val(), 'foobarfoobar');
         assert($("#new_message_content").is_focused());
         assert($("#send-status").visible());
-        assert.equal($("#compose-send-button").attr('disabled'), undefined);
+        assert.equal($("#compose-send-button").prop('disabled'), false);
         assert(!$("#sending-indicator").visible());
     }());
 }());
@@ -565,7 +565,7 @@ people.add(bob);
 (function test_finish() {
     (function test_when_compose_validation_fails() {
         $("#compose_invite_users").show();
-        $("#compose-send-button").removeAttr('disabled');
+        $("#compose-send-button").prop('disabled', false);
         $("#compose-send-button").focus();
         $("#sending-indicator").hide();
         $("#new_message_content").select(noop);
@@ -575,7 +575,7 @@ people.add(bob);
         assert(!$("#compose_invite_users").visible());
         assert(!$("#sending-indicator").visible());
         assert(!$("#compose-send-button").is_focused());
-        assert.equal($("#compose-send-button").attr('disabled'), undefined);
+        assert.equal($("#compose-send-button").prop('disabled'), false);
         assert.equal($('#error-msg').html(), i18n.t('You have nothing to send!'));
     }());
 
@@ -1051,7 +1051,7 @@ function test_with_mock_socket(test_params) {
         };
         var invite_err_sel = '.compose_invite_user_error';
         container.set_find_results(invite_err_sel, $(invite_err_sel));
-        target.removeAttr('disabled');
+        target.prop('disabled', false);
         $(invite_err_sel).hide();
 
         handler(event);
@@ -1269,7 +1269,7 @@ function test_with_mock_socket(test_params) {
 }());
 
 (function test_upload_started() {
-    $("#compose-send-button").removeAttr('disabled');
+    $("#compose-send-button").prop('disabled', false);
     $("#send-status").removeClass("alert-info").hide();
     $(".send-status-close").one = function (ev_name, handler) {
         assert.equal(ev_name, 'click');
@@ -1314,7 +1314,7 @@ function test_with_mock_socket(test_params) {
     function assert_side_effects(msg) {
         assert($("#send-status").hasClass("alert-error"));
         assert(!$("#send-status").hasClass("alert-info"));
-        assert.equal($("#compose-send-button").attr("disabled"), undefined);
+        assert.equal($("#compose-send-button").prop("disabled"), false);
         assert.equal($("#error-msg").text(), msg);
     }
 
@@ -1388,7 +1388,7 @@ function test_with_mock_socket(test_params) {
             if (response.uri) {
                 assert(compose_actions_start_checked);
                 assert(compose_ui_autosize_textarea_checked);
-                assert.equal($("#compose-send-button").attr('disabled'), undefined);
+                assert.equal($("#compose-send-button").prop('disabled'), false);
                 assert(!$('#send-status').hasClass('alert-info'));
                 assert(!$('#send-status').visible());
                 assert(clear_out_file_input_triggered);
diff --git a/frontend_tests/node_tests/settings_org.js b/frontend_tests/node_tests/settings_org.js
index 72a227bacd..8b0e3de734 100644
--- a/frontend_tests/node_tests/settings_org.js
+++ b/frontend_tests/node_tests/settings_org.js
@@ -334,7 +334,7 @@ function test_change_message_editing(change_message_editing) {
 
     change_message_editing.apply({checked: true});
     assert(!parent_elem.hasClass('control-label-disabled'));
-    assert.equal($('#id_realm_message_content_edit_limit_minutes').attr('disabled'), undefined);
+    assert.equal($('#id_realm_message_content_edit_limit_minutes').prop('disabled'), false);
 }
 
 function test_change_invite_required(change_invite_required) {
@@ -348,7 +348,7 @@ function test_change_invite_required(change_invite_required) {
 
     change_invite_required.apply({checked: true});
     assert(!parent_elem.hasClass('control-label-disabled'));
-    assert.equal($('#id_realm_invite_by_admins_only').attr('disabled'), undefined);
+    assert.equal($('#id_realm_invite_by_admins_only').prop('disabled'), false);
 }
 
 function test_disable_notifications_stream(disable_notifications_stream) {
@@ -506,7 +506,7 @@ function test_change_allow_subdomains(change_allow_subdomains) {
 
     $('#full_name').attr('disabled', 'disabled');
     settings_org.toggle_name_change_display();
-    assert.equal($('#full_name').attr('disabled'), undefined);
+    assert.equal($('#full_name').prop('disabled'), false);
     assert(name_toggled);
 
     settings_org.toggle_name_change_display();
diff --git a/static/js/activity.js b/static/js/activity.js
index 289e85414e..6d62c5d586 100644
--- a/static/js/activity.js
+++ b/static/js/activity.js
@@ -494,7 +494,7 @@ function update_clear_search_button() {
 
     // Show button iff the search input is focused, or has non-empty contents
     if (focused || $('.user-list-filter').val()) {
-        $('#clear_search_people_button').removeAttr('disabled');
+        $('#clear_search_people_button').prop('disabled', false);
     } else {
         $('#clear_search_people_button').attr('disabled', 'disabled');
     }
diff --git a/static/js/compose.js b/static/js/compose.js
index e2ed5ac354..110051ec71 100644
--- a/static/js/compose.js
+++ b/static/js/compose.js
@@ -91,7 +91,7 @@ function update_fade() {
 }
 
 exports.abort_xhr = function () {
-    $("#compose-send-button").removeAttr("disabled");
+    $("#compose-send-button").prop("disabled", false);
     var xhr = $("#compose").data("filedrop_xhr");
     if (xhr !== undefined) {
         xhr.abort();
@@ -150,7 +150,7 @@ function compose_error(error_text, bad_input) {
                .addClass('alert-error')
                .stop(true).fadeTo(0, 1);
     $('#error-msg').html(error_text);
-    $("#compose-send-button").removeAttr('disabled');
+    $("#compose-send-button").prop('disabled', false);
     $("#sending-indicator").hide();
     if (bad_input !== undefined) {
         bad_input.focus().select();
@@ -279,7 +279,7 @@ function clear_compose_box() {
     drafts.delete_draft_after_send();
     compose_ui.autosize_textarea();
     $("#send-status").hide(0);
-    $("#compose-send-button").removeAttr('disabled');
+    $("#compose-send-button").prop('disabled', false);
     $("#sending-indicator").hide();
     resize.resize_bottom_whitespace();
 }
@@ -457,7 +457,7 @@ function validate_stream_message_mentions(stream_name) {
             // user has not seen a warning message yet if undefined
             show_all_everyone_warnings();
 
-            $("#compose-send-button").removeAttr('disabled');
+            $("#compose-send-button").prop('disabled', false);
             $("#sending-indicator").hide();
             return false;
         }
@@ -799,7 +799,7 @@ exports.initialize = function () {
         var msg;
         $("#send-status").addClass("alert-error")
                         .removeClass("alert-info");
-        $("#compose-send-button").removeAttr("disabled");
+        $("#compose-send-button").prop("disabled", false);
         switch (err) {
         case 'BrowserNotSupported':
             msg = i18n.t("File upload is not yet available for your browser.");
@@ -849,7 +849,7 @@ exports.initialize = function () {
             textbox.val(textbox.val() + "[" + filename + "](" + uri + ")" + " ");
         }
         compose_ui.autosize_textarea();
-        $("#compose-send-button").removeAttr("disabled");
+        $("#compose-send-button").prop("disabled", false);
         $("#send-status").removeClass("alert-info")
                          .hide();
 
diff --git a/static/js/search.js b/static/js/search.js
index eaa41327f6..40736ae549 100644
--- a/static/js/search.js
+++ b/static/js/search.js
@@ -26,7 +26,7 @@ function update_buttons_with_focus(focused) {
     if (focused
         || search_query.val()
         || narrow_state.active()) {
-        $('.search_button').removeAttr('disabled');
+        $('.search_button').prop('disabled', false);
     } else {
         $('.search_button').attr('disabled', 'disabled');
     }
diff --git a/static/js/settings_notifications.js b/static/js/settings_notifications.js
index 54eb4045f8..99d0c555d5 100644
--- a/static/js/settings_notifications.js
+++ b/static/js/settings_notifications.js
@@ -77,10 +77,10 @@ exports.set_up = function () {
 
     $("#enable_desktop_notifications").change(function () {
         if (this.checked) {
-            $("#pm_content_in_desktop_notifications").removeAttr("disabled");
+            $("#pm_content_in_desktop_notifications").prop("disabled", false);
             $("#pm_content_in_desktop_notifications_label").parent().removeClass("control-label-disabled");
         } else {
-            $("#pm_content_in_desktop_notifications").attr("disabled", true);
+            $("#pm_content_in_desktop_notifications").prop("disabled", true);
             $("#pm_content_in_desktop_notifications_label").parent().addClass("control-label-disabled");
         }
     });
diff --git a/static/js/settings_org.js b/static/js/settings_org.js
index 234486ec55..5850b16031 100644
--- a/static/js/settings_org.js
+++ b/static/js/settings_org.js
@@ -49,7 +49,7 @@ exports.toggle_name_change_display = function () {
     }
 
     if ($('#full_name').attr('disabled')) {
-        $('#full_name').removeAttr('disabled');
+        $('#full_name').prop('disabled', false);
     } else {
         $('#full_name').attr('disabled', 'disabled');
     }
@@ -311,7 +311,7 @@ function _set_up() {
 
     $("#id_realm_invite_required").change(function () {
         if (this.checked) {
-            $("#id_realm_invite_by_admins_only").removeAttr("disabled");
+            $("#id_realm_invite_by_admins_only").prop("disabled", false);
             $("#id_realm_invite_by_admins_only_label").parent().removeClass("control-label-disabled");
         } else {
             $("#id_realm_invite_by_admins_only").attr("disabled", true);
@@ -321,7 +321,7 @@ function _set_up() {
 
     $("#id_realm_allow_message_editing").change(function () {
         if (this.checked) {
-            $("#id_realm_message_content_edit_limit_minutes").removeAttr("disabled");
+            $("#id_realm_message_content_edit_limit_minutes").prop("disabled", false);
             $("#id_realm_message_content_edit_limit_minutes_label").parent().removeClass("control-label-disabled");
         } else {
             $("#id_realm_message_content_edit_limit_minutes").attr("disabled", true);
diff --git a/static/js/stream_edit.js b/static/js/stream_edit.js
index c6129d4d4d..fe7b0296d9 100644
--- a/static/js/stream_edit.js
+++ b/static/js/stream_edit.js
@@ -256,7 +256,7 @@ function stream_home_view_clicked(e) {
     if (sub.in_home_view) {
         sub_settings.find(".mute-note").addClass("hide-mute-note");
         notification_checkboxes.removeClass("muted-sub");
-        notification_checkboxes.find("input[type='checkbox']").removeAttr("disabled");
+        notification_checkboxes.find("input[type='checkbox']").prop("disabled", false);
     } else {
         sub_settings.find(".mute-note").removeClass("hide-mute-note");
         notification_checkboxes.addClass("muted-sub");
diff --git a/static/js/stream_list.js b/static/js/stream_list.js
index 45a198a834..d57e686c30 100644
--- a/static/js/stream_list.js
+++ b/static/js/stream_list.js
@@ -537,7 +537,7 @@ exports.initiate_search = function () {
     var filter = $('.stream-list-filter').expectOne();
     filter.parent().removeClass('notdisplayed');
     filter.focus();
-    $('#clear_search_stream_button').removeAttr('disabled');
+    $('#clear_search_stream_button').prop('disabled', false);
 };
 
 exports.clear_and_hide_search = function () {
diff --git a/static/third/jquery-form/jquery.form.js b/static/third/jquery-form/jquery.form.js
index 13e9a55c58..c31c6b77c1 100644
--- a/static/third/jquery-form/jquery.form.js
+++ b/static/third/jquery-form/jquery.form.js
@@ -281,7 +281,7 @@ $.fn.ajaxSubmit = function(options) {
                 if ( useProp )
                     el.prop('disabled', false);
                 else
-                    el.removeAttr('disabled');
+                    el.prop('disabled', false);
             }
         }