diff --git a/base64url/index.js b/base64url/index.js
index f98d466..b53b196 100644
--- a/base64url/index.js
+++ b/base64url/index.js
@@ -12,11 +12,12 @@
  *
  * @returns base64url {String} : a base64url encoded string
  */
-const encodeBase64URL = (dataStr) => {
-    let base64 = window.btoa(dataStr);
-    let base64url = base64.split('=')[0]; // Remove any trailing '='s
+var encodeBase64URL = function encodeBase64URL(dataStr) {
+    var base64 = window.btoa(dataStr);
+    var base64url = base64.split('=')[0]; // Remove any trailing '='s
 
     base64url = base64url.replace(/\+/g, '-'); // 62nd char of encoding
+
     base64url = base64url.replace(/\//g, '_'); // 63rd char of encoding
 
     return base64url;
@@ -35,22 +36,33 @@ const encodeBase64URL = (dataStr) => {
  *
  * @returns {String} - a regular string
  */
-const decodeBase64URL = (str) => {
-    let base64 = str;
+var decodeBase64URL = function decodeBase64URL(str) {
+    var base64 = str;
     base64 = base64.replace(/-/g, '+'); // 62nd char of encoding
+
     base64 = base64.replace(/_/g, '/'); // 63rd char of encoding
-    switch (base64.length % 4) // Pad with trailing '='s
-    {
+
+    switch (base64.length % 4) {
+        // Pad with trailing '='s
         case 0:
-            break; // No pad chars in this case
+            break;
+        // No pad chars in this case
+
         case 2:
-            base64 += "=="; break; // Two pad chars
+            base64 += "==";
+            break;
+        // Two pad chars
+
         case 3:
-            base64 += "="; break; // One pad char
+            base64 += "=";
+            break;
+        // One pad char
+
         default:
-            if(window.console && window.console.log){
+            if (window.console && window.console.log) {
                 window.console.log('### base64url::decodeBase64URL::  Illegal base64url string!');
             }
+
     }
 
     try {
@@ -60,8 +72,8 @@ const decodeBase64URL = (str) => {
     }
 };
 
-const base64URL = {
-    encode : encodeBase64URL,
+var base64URL = {
+    encode: encodeBase64URL,
     decode: decodeBase64URL
 };
 
diff --git a/browser/index.js b/browser/index.js
index 89915cc..7dbcf9c 100644
--- a/browser/index.js
+++ b/browser/index.js
@@ -9,34 +9,29 @@
  *
  * @returns {Object} - browserInfo an object containing the retrieved browser properties
  */
-const collectBrowserInfo = () => {
+var collectBrowserInfo = function collectBrowserInfo() {
+    var screenWidth = window && window.screen ? window.screen.width : '';
+    var screenHeight = window && window.screen ? window.screen.height : '';
+    var colorDepth = window && window.screen ? window.screen.colorDepth : '';
+    var userAgent = window && window.navigator ? window.navigator.userAgent : '';
+    var javaEnabled = window && window.navigator ? navigator.javaEnabled() : false;
+    var language = '';
 
-    const screenWidth = window && window.screen ? window.screen.width : '';
-    const screenHeight = window && window.screen ? window.screen.height : '';
-    const colorDepth = window && window.screen ? window.screen.colorDepth : '';
-    const userAgent = window && window.navigator ? window.navigator.userAgent : '';
-    const javaEnabled = window && window.navigator ? navigator.javaEnabled() : false;
-
-    let language = '';
     if (window && window.navigator) {
-        language = window.navigator.language
-            ? window.navigator.language
-            : window.navigator.browserLanguage; // Else is for IE <+ 10
+        language = window.navigator.language ? window.navigator.language : window.navigator.browserLanguage; // Else is for IE <+ 10
     }
 
-    const d = new Date();
-    const timeZoneOffset = d.getTimezoneOffset();
-
-    const browserInfo = {
-        screenWidth,
-        screenHeight,
-        colorDepth,
-        userAgent,
-        timeZoneOffset,
-        language,
-        javaEnabled,
+    var d = new Date();
+    var timeZoneOffset = d.getTimezoneOffset();
+    var browserInfo = {
+        screenWidth: screenWidth,
+        screenHeight: screenHeight,
+        colorDepth: colorDepth,
+        userAgent: userAgent,
+        timeZoneOffset: timeZoneOffset,
+        language: language,
+        javaEnabled: javaEnabled
     };
-
     return browserInfo;
 };
 
diff --git a/dist/threeds2-js-utils.js b/dist/threeds2-js-utils.js
index 939262a..1da1f4b 100644
--- a/dist/threeds2-js-utils.js
+++ b/dist/threeds2-js-utils.js
@@ -1 +1 @@
-!function(e,n){"object"===typeof exports&&"object"===typeof module?module.exports=n():"function"===typeof define&&define.amd?define([],n):"object"===typeof exports?exports.ThreedDS2Utils=n():e.ThreedDS2Utils=n()}(this,function(){return function(e){var n={};function t(r){if(n[r])return n[r].exports;var o=n[r]={i:r,l:!1,exports:{}};return e[r].call(o.exports,o,o.exports,t),o.l=!0,o.exports}return t.m=e,t.c=n,t.d=function(e,n,r){t.o(e,n)||Object.defineProperty(e,n,{enumerable:!0,get:r})},t.r=function(e){"undefined"!==typeof Symbol&&Symbol.toStringTag&&Object.defineProperty(e,Symbol.toStringTag,{value:"Module"}),Object.defineProperty(e,"__esModule",{value:!0})},t.t=function(e,n){if(1&n&&(e=t(e)),8&n)return e;if(4&n&&"object"===typeof e&&e&&e.__esModule)return e;var r=Object.create(null);if(t.r(r),Object.defineProperty(r,"default",{enumerable:!0,value:e}),2&n&&"string"!=typeof e)for(var o in e)t.d(r,o,function(n){return e[n]}.bind(null,o));return r},t.n=function(e){var n=e&&e.__esModule?function(){return e.default}:function(){return e};return t.d(n,"a",n),n},t.o=function(e,n){return Object.prototype.hasOwnProperty.call(e,n)},t.p="",t(t.s=0)}([function(e,n,t){"use strict";t.r(n);var r={container:void 0},o={"01":["250px","400px"],"02":["390px","400px"],"03":["500px","600px"],"04":["600px","400px"],"05":["100%","100%"]};function a(e){return o.hasOwnProperty(e)?e:"01"}var i={createIframe:function(e,n){var t=arguments.length>2&&void 0!==arguments[2]?arguments[2]:"0",o=arguments.length>3&&void 0!==arguments[3]?arguments[3]:"0",a=arguments.length>4?arguments[4]:void 0;if(!n||0===n.length)throw new Error("Name parameter missing for iframe");e instanceof HTMLElement?r.container=e:r.container=document.body;var i=document.createElement("iframe");i.classList.add(n+"Class"),i.width=t,i.height=o,i.name=n,i.setAttribute("frameborder","0"),i.setAttribute("border","0");var d=document.createTextNode("<p>Your browser does not support iframes.</p>");return i.appendChild(d),r.container.appendChild(i),function(e,n){e.attachEvent?e.attachEvent("onload",function(){n&&"function"===typeof n&&n(e.contentWindow)}):e.onload=function(){n&&"function"===typeof n&&n(e.contentWindow)}}(i,a),i},createForm:function(e,n,t,r,o){if(!e||!n||!t||!r||!o)throw new Error("Not all required parameters provided for form creation");if(0===e.length||0===n.length||0===t.length||0===r.length||0===o.length)throw new Error("Not all required parameters have suitable values");var a=document.createElement("form");a.style.display="none",a.name=e,a.action=n,a.method="POST",a.target=t;var i=document.createElement("input");return i.name=r,i.value=o,a.appendChild(i),a},getBrowserInfo:function(){var e=window&&window.screen?window.screen.width:"",n=window&&window.screen?window.screen.height:"",t=window&&window.screen?window.screen.colorDepth:"",r=window&&window.navigator?window.navigator.userAgent:"",o=!(!window||!window.navigator)&&navigator.javaEnabled(),a="";return window&&window.navigator&&(a=window.navigator.language?window.navigator.language:window.navigator.browserLanguage),{screenWidth:e,screenHeight:n,colorDepth:t,userAgent:r,timeZoneOffset:(new Date).getTimezoneOffset(),language:a,javaEnabled:o}},base64Url:{encode:function(e){var n=window.btoa(e).split("=")[0];return n=(n=n.replace("/+/g","-")).replace("///g","_")},decode:function(e){var n=e;switch((n=(n=n.replace("/-/g","+")).replace("/_/g","/")).length%4){case 0:break;case 2:n+="==";break;case 3:n+="=";break;default:window.console&&window.console.log&&window.console.log("### base64url::decodeBase64URL::  Illegal base64url string!")}try{return window.atob(n)}catch(e){throw new Error(e)}}},config:{challengeWindowSizes:o,validateChallengeWindowSize:a,getChallengeWindowSize:function(e){return o[a(e)]},THREEDS_METHOD_TIMEOUT:1e4,CHALLENGE_TIMEOUT:6e5}};n.default=i}]).default});
\ No newline at end of file
+!function(e,n){"object"===typeof exports&&"object"===typeof module?module.exports=n():"function"===typeof define&&define.amd?define([],n):"object"===typeof exports?exports.ThreedDS2Utils=n():e.ThreedDS2Utils=n()}(this,function(){return function(e){var n={};function t(r){if(n[r])return n[r].exports;var o=n[r]={i:r,l:!1,exports:{}};return e[r].call(o.exports,o,o.exports,t),o.l=!0,o.exports}return t.m=e,t.c=n,t.d=function(e,n,r){t.o(e,n)||Object.defineProperty(e,n,{enumerable:!0,get:r})},t.r=function(e){"undefined"!==typeof Symbol&&Symbol.toStringTag&&Object.defineProperty(e,Symbol.toStringTag,{value:"Module"}),Object.defineProperty(e,"__esModule",{value:!0})},t.t=function(e,n){if(1&n&&(e=t(e)),8&n)return e;if(4&n&&"object"===typeof e&&e&&e.__esModule)return e;var r=Object.create(null);if(t.r(r),Object.defineProperty(r,"default",{enumerable:!0,value:e}),2&n&&"string"!=typeof e)for(var o in e)t.d(r,o,function(n){return e[n]}.bind(null,o));return r},t.n=function(e){var n=e&&e.__esModule?function(){return e.default}:function(){return e};return t.d(n,"a",n),n},t.o=function(e,n){return Object.prototype.hasOwnProperty.call(e,n)},t.p="",t(t.s=0)}([function(e,n,t){"use strict";t.r(n);var r={container:void 0},o={"01":["250px","400px"],"02":["390px","400px"],"03":["500px","600px"],"04":["600px","400px"],"05":["100%","100%"]};function a(e){var n=1===e.length?"0".concat(e):e;return o.hasOwnProperty(n)?n:"01"}var i={createIframe:function(e,n){var t=arguments.length>2&&void 0!==arguments[2]?arguments[2]:"0",o=arguments.length>3&&void 0!==arguments[3]?arguments[3]:"0",a=arguments.length>4?arguments[4]:void 0;if(!n||0===n.length)throw new Error("Name parameter missing for iframe");e instanceof HTMLElement?r.container=e:r.container=document.body;var i=document.createElement("iframe");i.classList.add(n+"Class"),i.width=t,i.height=o,i.name=n,i.setAttribute("frameborder","0"),i.setAttribute("border","0");var d=document.createTextNode("<p>Your browser does not support iframes.</p>");return i.appendChild(d),r.container.appendChild(i),function(e,n){e.attachEvent?e.attachEvent("onload",function(){n&&"function"===typeof n&&n(e.contentWindow)}):e.onload=function(){n&&"function"===typeof n&&n(e.contentWindow)}}(i,a),i},createForm:function(e,n,t,r,o){if(!e||!n||!t||!r||!o)throw new Error("Not all required parameters provided for form creation");if(0===e.length||0===n.length||0===t.length||0===r.length||0===o.length)throw new Error("Not all required parameters have suitable values");var a=document.createElement("form");a.style.display="none",a.name=e,a.action=n,a.method="POST",a.target=t;var i=document.createElement("input");return i.name=r,i.value=o,a.appendChild(i),a},getBrowserInfo:function(){var e=window&&window.screen?window.screen.width:"",n=window&&window.screen?window.screen.height:"",t=window&&window.screen?window.screen.colorDepth:"",r=window&&window.navigator?window.navigator.userAgent:"",o=!(!window||!window.navigator)&&navigator.javaEnabled(),a="";return window&&window.navigator&&(a=window.navigator.language?window.navigator.language:window.navigator.browserLanguage),{screenWidth:e,screenHeight:n,colorDepth:t,userAgent:r,timeZoneOffset:(new Date).getTimezoneOffset(),language:a,javaEnabled:o}},base64Url:{encode:function(e){var n=window.btoa(e).split("=")[0];return n=(n=n.replace(/\+/g,"-")).replace(/\//g,"_")},decode:function(e){var n=e;switch((n=(n=n.replace(/-/g,"+")).replace(/_/g,"/")).length%4){case 0:break;case 2:n+="==";break;case 3:n+="=";break;default:window.console&&window.console.log&&window.console.log("### base64url::decodeBase64URL::  Illegal base64url string!")}try{return window.atob(n)}catch(e){throw new Error(e)}}},config:{challengeWindowSizes:o,validateChallengeWindowSize:a,getChallengeWindowSize:function(e){return o[a(e)]},THREEDS_METHOD_TIMEOUT:1e4,CHALLENGE_TIMEOUT:6e5}};n.default=i}]).default});
\ No newline at end of file
diff --git a/form/index.js b/form/index.js
index 2e1541d..54d93c2 100644
--- a/form/index.js
+++ b/form/index.js
@@ -11,8 +11,7 @@
  *
  * @returns {Element} - Created form element
  */
-const createForm = (name, action, target, inputName, inputValue) => {
-
+var createForm = function createForm(name, action, target, inputName, inputValue) {
     if (!name || !action || !target || !inputName || !inputValue) {
         throw new Error('Not all required parameters provided for form creation');
     }
@@ -21,16 +20,16 @@ const createForm = (name, action, target, inputName, inputValue) => {
         throw new Error('Not all required parameters have suitable values');
     }
 
-    const form = document.createElement( 'form' );
+    var form = document.createElement('form');
     form.style.display = 'none';
     form.name = name;
     form.action = action;
-    form.method = "POST";
+    form.method = 'POST';
     form.target = target;
-    const input = document.createElement( 'input' );
+    var input = document.createElement('input');
     input.name = inputName;
     input.value = inputValue;
-    form.appendChild( input );
+    form.appendChild(input);
     return form;
 };
 
diff --git a/iframe/index.js b/iframe/index.js
index 0591787..71bff76 100644
--- a/iframe/index.js
+++ b/iframe/index.js
@@ -1,16 +1,16 @@
-const configObject = {};
+var configObject = {};
 configObject.container = void 0;
 
-const addIframeListener = (iframe, callback) => {
-    if (iframe.attachEvent){
+var addIframeListener = function addIframeListener(iframe, callback) {
+    if (iframe.attachEvent) {
         // IE fallback
-        iframe.attachEvent("onload", function(){
+        iframe.attachEvent("onload", function () {
             if (callback && typeof callback === "function") {
                 callback(iframe.contentWindow);
             }
         });
     } else {
-        iframe.onload = function(){
+        iframe.onload = function () {
             if (callback && typeof callback === "function") {
                 callback(iframe.contentWindow);
             }
@@ -31,34 +31,33 @@ const addIframeListener = (iframe, callback) => {
  *
  * @returns {Element} - Created iframe element
  */
-const createIframe = (container, name, width = '0', height = '0', callback) => {
-    if (!name || name.length === 0){
+var createIframe = function createIframe(container, name) {
+    var width = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : '0';
+    var height = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : '0';
+    var callback = arguments.length > 4 ? arguments[4] : undefined;
+
+    if (!name || name.length === 0) {
         throw new Error('Name parameter missing for iframe');
-    }
+    } // Resolve holding element for generated iframe else default to body
+
 
-    // Resolve holding element for generated iframe else default to body
     if (container instanceof HTMLElement) {
         configObject.container = container;
     } else {
         configObject.container = document.body;
     }
 
-    const iframe = document.createElement('iframe');
-
+    var iframe = document.createElement('iframe');
     iframe.classList.add(name + 'Class');
     iframe.width = width;
     iframe.height = height;
     iframe.name = name;
     iframe.setAttribute('frameborder', '0');
     iframe.setAttribute('border', '0');
-
-    const noIframeElContent = document.createTextNode('<p>Your browser does not support iframes.</p>');
+    var noIframeElContent = document.createTextNode('<p>Your browser does not support iframes.</p>');
     iframe.appendChild(noIframeElContent);
-
     configObject.container.appendChild(iframe);
-
     addIframeListener(iframe, callback);
-
     return iframe;
 };