Prefer .nhsuk-frontend-supported to .js-enabled

We must avoid adding styles for Internet Explorer 11 (and other older browsers) where support for `<script type="module">` is not available

Author: colinrotherham

backstop.config.js

@@ -80,7 +80,7 @@ module.exports = {
     engine_scripts: 'tests/backstop/engine_scripts',
     html_report: 'tests/backstop/html_report'
   },
-  readySelector: 'body.js-enabled',
+  readySelector: 'body.nhsuk-frontend-supported',
   report: ['browser'],
   scenarios: [
     {

docs/contributing/coding-standards.md

@@ -147,7 +147,7 @@ Bad:
 ```scss
 .nhsuk-checkboxes__conditional {
   // ...
-  .js-enabled &--hidden {
+  .nhsuk-frontend-supported &--hidden {
     // ...
   }
  // ...
@@ -161,7 +161,7 @@ Good:
   // ...
 }
 
-.js-enabled .nhsuk-checkboxes__conditional--hidden {
+.nhsuk-frontend-supported .nhsuk-checkboxes__conditional--hidden {
   // ...
 }
 ```

packages/components/checkboxes/_index.scss

@@ -150,6 +150,6 @@ $nhsuk-checkboxes-label-padding-left-right: 12px;
   }
 }
 
-.js-enabled .nhsuk-checkboxes__conditional--hidden {
+.nhsuk-frontend-supported .nhsuk-checkboxes__conditional--hidden {
   display: none;
 }

packages/components/header/_header-base.scss

@@ -484,7 +484,7 @@
     justify-content: space-between;
   }
 
-  .js-enabled & {
+  .nhsuk-frontend-supported & {
     flex-wrap: nowrap;
     overflow: hidden;
   }

packages/components/radios/_index.scss

@@ -175,6 +175,6 @@ $nhsuk-radios-focus-width: $nhsuk-focus-width + 1px;
   }
 }
 
-.js-enabled .nhsuk-radios__conditional--hidden {
+.nhsuk-frontend-supported .nhsuk-radios__conditional--hidden {
   display: none;
 }

packages/components/tabs/_index.scss

@@ -41,8 +41,8 @@
   @include nhsuk-responsive-margin(8, "bottom");
 }
 
-// JavaScript enabled
-.js-enabled {
+// ES module JavaScript supported
+.nhsuk-frontend-supported {
   @include nhsuk-media-query($from: tablet) {
     .nhsuk-tabs__list {
       border-bottom: 1px solid $nhsuk-border-color;