Jorge Dias

So many layers of web

The problem we have is that this code

new Element('div', {'class':'klassName'})

will work in firefox but in IE (tested on version 8) the className is never set, which was causing some problems with the elements styles.

One of the workarounds would be to explicitly add the class name, like this:

var e = new Element('div');

The problem with this approach is that at work, we have a huge javascript codebase, so instead, we are going to monkey patch Prototype. We’re working against version of prototype, that’s why we add the alert, so when we update, we’ll catch this and check if it was fixed on core.

// This is a dirty hack to protoype, so IE, will take class names on new Element
// new Element('div', {'class':'klassName'}) doesn't work on IE but does on firefox
// in IE, we wouldn't get the className set.

if (Prototype.Version != '') alert("BEWARE OF THE PROTOTYPE VERSION");

(function() {
   var element = this.Element;
   this.Element = function(tagName, attributes) {
     attributes = attributes || { };
     tagName = tagName.toLowerCase();
     var cache = Element.cache;
     if (Prototype.Browser.IE && ( || attributes['class'])) {
       tagName = '<' + tagName + ' name="' + + '"' + 'class="' + attributes['class'] + '"' + '>';

       return Element.writeAttribute(document.createElement(tagName), attributes);
     if (!cache[tagName]) cache[tagName] = Element.extend(document.createElement(tagName));
     return Element.writeAttribute(cache[tagName].cloneNode(false), attributes);
   Object.extend(this.Element, element || { });
   if (element) this.Element.prototype = element.prototype;
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