Fix Unbounce forms in IE8

ie8-polyfill.js

(function() {
  if (!Object.keys) {
    Object.keys = function(o) {
      if (o !== Object(o)) {
        throw new TypeError('Object.keys called on a non-object');
      }
      var k=[],p;
      for (p in o) if (Object.prototype.hasOwnProperty.call(o,p)) k.push(p);
      return k;
    }
  }
  if (!Function.prototype.bind) {
    Function.prototype.bind = function(oThis) {
      if (typeof this !== 'function') {
        // closest thing possible to the ECMAScript 5
        // internal IsCallable function
        throw new TypeError('Function.prototype.bind - what is trying to be bound is not callable');
      }

      var aArgs   = Array.prototype.slice.call(arguments, 1),
          fToBind = this,
          fNOP    = function() {},
          fBound  = function() {
            return fToBind.apply(this instanceof fNOP
                                 ? this
                                 : oThis,
                                 aArgs.concat(Array.prototype.slice.call(arguments)));
          };

      if (this.prototype) {
        // Function.prototype doesn't have a prototype property
        fNOP.prototype = this.prototype;
      }
      fBound.prototype = new fNOP();

      return fBound;
    };
  }
  if (!Event.prototype.preventDefault) {
    Event.prototype.preventDefault=function() {
      this.returnValue=false;
    };
  }
  if (!Event.prototype.stopPropagation) {
    Event.prototype.stopPropagation=function() {
      this.cancelBubble=true;
    };
  }
  if (!Element.prototype.addEventListener) {
    var eventListeners=[];

    var addEventListener=function(type,listener /*, useCapture (will be ignored) */) {
      var self=this;
      var wrapper=function(e) {
        e.target=e.srcElement;
        e.currentTarget=self;
        if (typeof listener.handleEvent != 'undefined') {
          listener.handleEvent(e);
        } else {
          listener.call(self,e);
        }
      };
      if (type=="DOMContentLoaded") {
        var wrapper2=function(e) {
          if (document.readyState=="complete") {
            wrapper(e);
          }
        };
        document.attachEvent("onreadystatechange",wrapper2);
        eventListeners.push({object:this,type:type,listener:listener,wrapper:wrapper2});

        if (document.readyState=="complete") {
          var e=new Event();
          e.srcElement=window;
          wrapper2(e);
        }
      } else {
        this.attachEvent("on"+type,wrapper);
        eventListeners.push({object:this,type:type,listener:listener,wrapper:wrapper});
      }
    };
    var removeEventListener=function(type,listener /*, useCapture (will be ignored) */) {
      var counter=0;
      while (counter<eventListeners.length) {
        var eventListener=eventListeners[counter];
        if (eventListener.object==this && eventListener.type==type && eventListener.listener==listener) {
          if (type=="DOMContentLoaded") {
            this.detachEvent("onreadystatechange",eventListener.wrapper);
          } else {
            this.detachEvent("on"+type,eventListener.wrapper);
          }
          eventListeners.splice(counter, 1);
          break;
        }
        ++counter;
      }
    };
    Element.prototype.addEventListener=addEventListener;
    Element.prototype.removeEventListener=removeEventListener;
    if (HTMLDocument) {
      HTMLDocument.prototype.addEventListener=addEventListener;
      HTMLDocument.prototype.removeEventListener=removeEventListener;
    }
    if (Window) {
      Window.prototype.addEventListener=addEventListener;
      Window.prototype.removeEventListener=removeEventListener;
    }
  }
})();

ie8-polyfill.min.js

!function(){if(Object.keys||(Object.keys=function(a){if(a!==Object(a))throw new TypeError("Object.keys called on a non-object");var b,c=[];for(b in a)Object.prototype.hasOwnProperty.call(a,b)&&c.push(b);return c}),Function.prototype.bind||(Function.prototype.bind=function(a){if("function"!=typeof this)throw new TypeError("Function.prototype.bind - what is trying to be bound is not callable");var b=Array.prototype.slice.call(arguments,1),c=this,d=function(){},e=function(){return c.apply(this instanceof d?this:a,b.concat(Array.prototype.slice.call(arguments)))};return this.prototype&&(d.prototype=this.prototype),e.prototype=new d,e}),Event.prototype.preventDefault||(Event.prototype.preventDefault=function(){this.returnValue=!1}),Event.prototype.stopPropagation||(Event.prototype.stopPropagation=function(){this.cancelBubble=!0}),!Element.prototype.addEventListener){var a=[],b=function(b,c){var d=this,e=function(a){a.target=a.srcElement,a.currentTarget=d,"undefined"!=typeof c.handleEvent?c.handleEvent(a):c.call(d,a)};if("DOMContentLoaded"==b){var f=function(a){"complete"==document.readyState&&e(a)};if(document.attachEvent("onreadystatechange",f),a.push({object:this,type:b,listener:c,wrapper:f}),"complete"==document.readyState){var g=new Event;g.srcElement=window,f(g)}}else this.attachEvent("on"+b,e),a.push({object:this,type:b,listener:c,wrapper:e})},c=function(b,c){for(var d=0;d<a.length;){var e=a[d];if(e.object==this&&e.type==b&&e.listener==c){"DOMContentLoaded"==b?this.detachEvent("onreadystatechange",e.wrapper):this.detachEvent("on"+b,e.wrapper),a.splice(d,1);break}++d}};Element.prototype.addEventListener=b,Element.prototype.removeEventListener=c,HTMLDocument&&(HTMLDocument.prototype.addEventListener=b,HTMLDocument.prototype.removeEventListener=c),Window&&(Window.prototype.addEventListener=b,Window.prototype.removeEventListener=c)}}();