diff --git a/.eslintignore b/.eslintignore
index b4ad30abeb671..19f5a98b5fcef 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -61,6 +61,7 @@ lib/amd/src/popper.js
 lib/geopattern-php/
 lib/php-jwt/
 lib/babel-polyfill/
+lib/mdn-polyfills/
 lib/emoji-data/
 lib/h5p/
 media/player/videojs/amd/src/video-lazy.js
diff --git a/.stylelintignore b/.stylelintignore
index 989166f88c570..4d4c82ff8d206 100644
--- a/.stylelintignore
+++ b/.stylelintignore
@@ -62,6 +62,7 @@ lib/amd/src/popper.js
 lib/geopattern-php/
 lib/php-jwt/
 lib/babel-polyfill/
+lib/mdn-polyfills/
 lib/emoji-data/
 lib/h5p/
 media/player/videojs/amd/src/video-lazy.js
diff --git a/lib/mdn-polyfills/polyfill.js b/lib/mdn-polyfills/polyfill.js
new file mode 100644
index 0000000000000..c74b588f7878f
--- /dev/null
+++ b/lib/mdn-polyfills/polyfill.js
@@ -0,0 +1,18 @@
+!function(){function t(t,e){e=e||{bubbles:!1,cancelable:!1,detail:void 0};var n=document.createEvent("CustomEvent");return n.initCustomEvent(t,e.bubbles,e.cancelable,e.detail),n}"function"!=typeof window.CustomEvent&&(t.prototype=window.Event.prototype,window.CustomEvent=t)}();
+String.prototype.trim||(String.prototype.trim=function(){return this.replace(/^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g,"")}),!window.Element||"classList"in Element.prototype||function(e){function c(e,t){if(""===t)throw new DOMException("Failed to execute '"+e+"' on 'DOMTokenList': The token provided must not be empty.");if(-1!==(wsI=t.search(wsRE)))throw new DOMException("Failed to execute '"+e+"' on 'DOMTokenList': The token provided ('"+t[wsI]+"') contains HTML space characters, which are not valid in tokens.")}var t,n;"function"!=typeof DOMTokenList&&function(f){var t=f.document,e=f.Object,n=e.prototype.hasOwnProperty,v=e.defineProperty,i=0,g=0,d=(f.Element,/[\11\12\14\15\40]/);function s(){if(!i)throw TypeError("Illegal constructor")}function a(){var e=f.event,t=e.propertyName;if(!g&&("className"===t||"classList"===t&&!v)){var n=e.srcElement,r=n[" uCLp"],o=""+n[t],i=o.trim().split(d),s=n["classList"===t?" uCL":"classList"],a=r.length;e:for(var l=0,c=r.length=i.length,u=0;l!==c;++l){for(var h=0;h!==l;++h)if(i[h]===i[l]){u++;continue e}s[l-u]=i[l]}for(var p=c-u;p<a;++p)delete s[p];if("classList"!==t)return;g=1,n.classList=s,n.className=o,g=0,s.length=i.length-u}}function r(l){if(!(l&&"innerHTML"in l))throw TypeError("Illegal invocation");srcEle.detachEvent("onpropertychange",a),i=1;try{new s}finally{i=0}var c=protoObj.prototype,u=new protoObj;e:for(var e=l.className.trim().split(d),t=0,n=e.length,r=0;t!==n;++t){for(var o=0;o!==t;++o)if(e[o]===e[t]){r++;continue e}this[t-r]=e[t]}c.length=Len-r,c.value=l.className,c[" uCL"]=l,v?(v(l,"classList",{enumerable:1,get:function(){return u},configurable:0,set:function(e){g=1,l.className=c.value=e+="",g=0;var t=e.trim().split(d),n=c.length;e:for(var r=0,o=c.length=t.length,i=0;r!==o;++r){for(var s=0;s!==r;++s)if(t[s]===t[r]){i++;continue e}u[r-i]=t[r]}for(var a=o-i;a<n;++a)delete u[a]}}),v(l," uCLp",{enumerable:0,configurable:0,writeable:0,value:protoObj.prototype}),v(c," uCL",{enumerable:0,configurable:0,writeable:0,value:l})):(l.classList=u,l[" uCL"]=u,l[" uCLp"]=protoObj.prototype),srcEle.attachEvent("onpropertychange",a)}s.prototype.toString=s.prototype.toLocaleString=function(){return this.value},s.prototype.add=function(){e:for(var e=0,t=arguments.length,n="",r=this.uCL,o=r[" uCLp"];e!==t;++e){c("add",n=arguments[e]+"");for(var i=0,s=o.length,a=n;i!==s;++i){if(this[i]===n)continue e;a+=" "+this[i]}this[s]=n,o.length+=1,o.value=a}g=1,r.className=o.value,g=0},s.prototype.remove=function(){for(var e=0,t=arguments.length,n="",r=this.uCL,o=r[" uCLp"];e!==t;++e){c("remove",n=arguments[e]+"");for(var i=0,s=o.length,a="",l=0;i!==s;++i)l?this[i-1]=this[i]:this[i]!==n?a+=this[i]+" ":l=1;l&&(delete this[s],o.length-=1,o.value=a)}g=1,r.className=o.value,g=0},f.DOMTokenList=s;try{f.Object.defineProperty(f.Element.prototype,"classList",{enumerable:1,get:function(e){return n.call(f.Element.prototype,"classList")||r(this),this.classList},configurable:0,set:function(e){this.className=e}})}catch(e){f[" uCL"]=r,t.documentElement.firstChild.appendChild(t.createElement("style")).styleSheet.cssText='_*{x-uCLp:expression(!this.hasOwnProperty("classList")&&window[" uCL"](this))}[class]{x-uCLp/**/:expression(!this.hasOwnProperty("classList")&&window[" uCL"](this))}'}}(e),t=e.DOMTokenList.prototype,n=e.document.createElement("div").classList,t.item||(t.item=function(e){return void 0===(t=this[e])?null:t;var t}),t.toggle&&!1===n.toggle("a",0)||(t.toggle=function(e){if(1<arguments.length)return this[arguments[1]?"add":"remove"](e),!!arguments[1];var t=this.value;return this.remove(oldToken),t===this.value&&(this.add(e),!0)}),t.replace&&"boolean"==typeof n.replace("a","b")||(t.replace=function(e,t){c("replace",e),c("replace",t);var n=this.value;return this.remove(e),this.value!==n&&(this.add(t),!0)}),t.contains||(t.contains=function(e){for(var t=0,n=this.length;t!==n;++t)if(this[t]===e)return!0;return!1}),t.forEach||(t.forEach=function(e){if(1===arguments.length)for(var t=0,n=this.length;t!==n;++t)e(this[t],t,this);else{t=0,n=this.length;for(var r=arguments[1];t!==n;++t)e.call(r,this[t],t,this)}}),t.entries||(t.entries=function(){var e=this;return{next:function(){return 0<e.length?{value:[0,e[0]],done:!1}:{done:!0}}}}),t.values||(t.values=function(){var e=this;return{next:function(){return 0<e.length?{value:e[0],done:!1}:{done:!0}}}}),t.keys||(t.keys=function(){var e=this;return{next:function(){return 0<e.length?{value:0,done:!1}:{done:!0}}}})}(window);
+Element.prototype.matches||(Element.prototype.matches=Element.prototype.msMatchesSelector||Element.prototype.webkitMatchesSelector),window.Element&&!Element.prototype.closest&&(Element.prototype.closest=function(e){var t=this;do{if(t.matches(e))return t;t=t.parentElement||t.parentNode}while(null!==t&&1===t.nodeType);return null});
+Element.prototype.matches||(Element.prototype.matches=Element.prototype.msMatchesSelector||Element.prototype.webkitMatchesSelector);
+window.Element&&!Element.prototype.toggleAttribute&&(Element.prototype.toggleAttribute=function(t,e){var r=!!e,i=2===arguments.length&&!e;return null!==this.getAttribute(t)?!!r||(this.removeAttribute(t),!1):!i&&(this.setAttribute(t,""),!0)});
+Function.prototype.bind||(Function.prototype.bind=function(t){if("function"!=typeof this)throw new TypeError("Function.prototype.bind - what is trying to be bound is not callable");var o=Array.prototype.slice.call(arguments,1),n=this,i=function(){},r=function(){return n.apply(this instanceof i?this:t,o.concat(Array.prototype.slice.call(arguments)))};return this.prototype&&(i.prototype=this.prototype),r.prototype=new i,r});
+HTMLCanvasElement.prototype.toBlob||(HTMLCanvasElement.prototype.toBlob=function(a,r,t){var i=this.toDataURL(r,t).split(",")[1];setTimeout(function(){for(var t=atob(i),o=t.length,e=new Uint8Array(o),n=0;n<o;n++)e[n]=t.charCodeAt(n);a(new Blob([e],{type:r||"image/png"}))})});
+!function(){try{return new MouseEvent("test")}catch(e){}var e=function(e,t){t=t||{bubbles:!1,cancelable:!1};var n=document.createEvent("MouseEvent");return n.initMouseEvent(e,t.bubbles,t.cancelable,window,0,t.screenX||0,t.screenY||0,t.clientX||0,t.clientY||0,t.ctrlKey||!1,t.altKey||!1,t.shiftKey||!1,t.metaKey||!1,t.button||0,t.relatedTarget||null),n};e.prototype=Event.prototype,window.MouseEvent=e}();
+!function(){function e(e,t){var n=this,o=function(e){e.target=e.srcElement,e.currentTarget=n,void 0!==t.handleEvent?t.handleEvent(e):t.call(n,e)};if("DOMContentLoaded"==e){var r=function(e){"complete"==document.readyState&&o(e)};if(document.attachEvent("onreadystatechange",r),eventListeners.push({object:this,type:e,listener:t,wrapper:r}),"complete"==document.readyState){var a=new Event;a.srcElement=window,r(a)}}else this.attachEvent("on"+e,o),eventListeners.push({object:this,type:e,listener:t,wrapper:o})}function t(e,t){for(var n=0;n<eventListeners.length;){var o=eventListeners[n];if(o.object==this&&o.type==e&&o.listener==t){"DOMContentLoaded"==e?this.detachEvent("onreadystatechange",o.wrapper):this.detachEvent("on"+e,o.wrapper),eventListeners.splice(n,1);break}++n}}var n;n=window.Node||window.Element,Event.prototype.preventDefault||(Event.prototype.preventDefault=function(){this.returnValue=!1}),Event.prototype.stopPropagation||(Event.prototype.stopPropagation=function(){this.cancelBubble=!0}),n&&n.prototype&&null==n.prototype.addEventListener&&(n.prototype.addEventListener=e,n.prototype.removeEventListener=t,HTMLDocument&&(HTMLDocument.prototype.addEventListener=e,HTMLDocument.prototype.removeEventListener=t),Window&&(Window.prototype.addEventListener=e,Window.prototype.removeEventListener=t))}();
+!function(){function t(){var e=Array.prototype.slice.call(arguments),r=document.createDocumentFragment();e.forEach(function(e){var t=e instanceof Node;r.appendChild(t?e:document.createTextNode(String(e)))}),this.parentNode.insertBefore(r,this.nextSibling)}[Element.prototype,CharacterData.prototype,DocumentType.prototype].forEach(function(e){e.hasOwnProperty("after")||Object.defineProperty(e,"after",{configurable:!0,enumerable:!0,writable:!0,value:t})})}();
+!function(){function t(){var e=Array.prototype.slice.call(arguments),n=document.createDocumentFragment();e.forEach(function(e){var t=e instanceof Node;n.appendChild(t?e:document.createTextNode(String(e)))}),this.appendChild(n)}[Element.prototype,Document.prototype,DocumentFragment.prototype].forEach(function(e){e.hasOwnProperty("append")||Object.defineProperty(e,"append",{configurable:!0,enumerable:!0,writable:!0,value:t})})}();
+!function(){function t(){var e=Array.prototype.slice.call(arguments),o=document.createDocumentFragment();e.forEach(function(e){var t=e instanceof Node;o.appendChild(t?e:document.createTextNode(String(e)))}),this.parentNode.insertBefore(o,this)}[Element.prototype,CharacterData.prototype,DocumentType.prototype].forEach(function(e){e.hasOwnProperty("before")||Object.defineProperty(e,"before",{configurable:!0,enumerable:!0,writable:!0,value:t})})}();
+!function(){function e(){for(var e,o=0,t=this.childNodes,n=[];e=t[o++];)1===e.nodeType&&n.push(e);return n}var o;(o=window.Node||window.Element)&&o.prototype&&null==o.prototype.children&&Object.defineProperty(o.prototype,"children",{get:e})}();
+!function(){function e(){for(var e,t=this.childNodes,n=0;e=t[n++];)if(1===e.nodeType)return e;return null}var t;(t=window.Node||window.Element)&&t.prototype&&null==t.prototype.firstElementChild&&Object.defineProperty(t.prototype,"firstElementChild",{get:e})}();
+!function(){function t(){var e=Array.prototype.slice.call(arguments),n=document.createDocumentFragment();e.forEach(function(e){var t=e instanceof Node;n.appendChild(t?e:document.createTextNode(String(e)))}),this.insertBefore(n,this.firstChild)}[Element.prototype,Document.prototype,DocumentFragment.prototype].forEach(function(e){e.hasOwnProperty("prepend")||Object.defineProperty(e,"prepend",{configurable:!0,enumerable:!0,writable:!0,value:t})})}();
+!function(){function t(){null!==this.parentNode&&this.parentNode.removeChild(this)}[Element.prototype,CharacterData.prototype,DocumentType.prototype].forEach(function(e){e.hasOwnProperty("remove")||Object.defineProperty(e,"remove",{configurable:!0,enumerable:!0,writable:!0,value:t})})}();
+!function(){var r="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(e){return typeof e}:function(e){return e&&"function"==typeof Symbol&&e.constructor===Symbol&&e!==Symbol.prototype?"symbol":typeof e};function t(){var e,t=this.parentNode,o=arguments.length;if(t)for(o||t.removeChild(this);o--;)"object"!==(void 0===(e=arguments[o])?"undefined":r(e))?e=this.ownerDocument.createTextNode(e):e.parentNode&&e.parentNode.removeChild(e),o?t.insertBefore(this.previousSibling,e):t.replaceChild(e,this)}[Element.prototype,CharacterData.prototype,DocumentType.prototype].forEach(function(e){e.hasOwnProperty("replaceWith")||Object.defineProperty(e,"replaceWith",{configurable:!0,enumerable:!0,writable:!0,value:t})})}();
+window.NodeList&&!NodeList.prototype.forEach&&(NodeList.prototype.forEach=function(o,t){t=t||window;for(var i=0;i<this.length;i++)o.call(t,this[i],i,this)});
diff --git a/lib/mdn-polyfills/readme_moodle.txt b/lib/mdn-polyfills/readme_moodle.txt
new file mode 100644
index 0000000000000..2c0983eb70ee2
--- /dev/null
+++ b/lib/mdn-polyfills/readme_moodle.txt
@@ -0,0 +1,13 @@
+The steps are essentially:
+1) Install mdn-polyfills package
+
+    npm install --no-save  mdn-polyfills
+
+2) Join them all together:
+
+    cd node_modules/mdn-polyfills
+    cat CustomEvent.* Element.* Function.* HTMLCanvasElement.* MouseEvent.* Node.prototype.* NodeList.* > ../../lib/mdn-polyfills/polyfill.js
+
+3) Uninstall the package again
+
+    npm uninstall --no-save mdn-polyfills
diff --git a/lib/outputrequirementslib.php b/lib/outputrequirementslib.php
index 0b7d01addb46f..9dce334347725 100644
--- a/lib/outputrequirementslib.php
+++ b/lib/outputrequirementslib.php
@@ -1608,6 +1608,9 @@ public function get_top_of_body_code(renderer_base $renderer) {
             $output .= html_writer::script('', $this->js_fix_url('/lib/babel-polyfill/polyfill.min.js'));
         }
 
+        // Include the MDN Polyfill.
+        $output .= html_writer::script('', $this->js_fix_url('/lib/mdn-polyfills/polyfill.js'));
+
         // YUI3 JS needs to be loaded early in the body. It should be cached well by the browser.
         $output .= $this->get_yui3lib_headcode();
 
diff --git a/lib/thirdpartylibs.xml b/lib/thirdpartylibs.xml
index 89c1b67f1f47a..b76432fc6d1a4 100644
--- a/lib/thirdpartylibs.xml
+++ b/lib/thirdpartylibs.xml
@@ -308,6 +308,12 @@
     <license>MIT</license>
     <version>6.26.0</version>
   </library>
+  <library>
+    <location>mdn-polyfills</location>
+    <name>mdn-polyfill</name>
+    <license>MIT</license>
+    <version>5.19.0</version>
+  </library>
   <library>
     <location>emoji-data</location>
     <name>Emoji data</name>