Glad you like it!

Seb,

Ah, it was due to trying to prevent some WordPress escaping. The code in the post is ok now too.

I have no information about performance, but it seems a bit superfluous to add the method to every element in the web page. When it comes to calling the method on an element itself, though, I agree that it is a nicer approach.

My suggestion is to only add the method to elements that need it, and it’s the base approach of my DOMAssistant library.

Now I don’t know whether it is bad for the overall performance when you add functions to the Node prototype itself, but that’s what I just did: Now you can call the function on any node to get elements of given classnames inside of it. Of course you can use it on the document node itself too, to get all matching elements in the whole documnt.
Maybe this is a good place to get some profound answers to the performance question - Does one have to be careful with Node-prototype-functions regarding the performance of the site/document??
However, here are some examples of how to call the version changed by me:

var e = document.getElementsByClassName('green')[0];
var form = document.getElementsByClassName(’floating login box’, ‘form’);
var form = document.getElementsByClassName(’login box floating’, ‘form’);
/* if you need only elements within a specific element: */
var container = document.getElementById(’container’);
var boxes = container.getElementsByClassName(’box’);
/* handy: */
var boxes = $(’container’).getElementsByClassName(’box’);


So here is the changed version:

Node.prototype.getElementsByClassName = function () {
/*
Written by Jonathan Snook, http://www.snook.ca/jonathan
Add-ons by Robert Nyman, http://www.robertnyman.com
and Jovica Aleksik, loopmode@loopmode.de
arguments: className, [tagName]
*/
if (this.nodeType != 9) {
return;
}
var oElm = this;
var oClassNames = arguments[0].indexOf(’ ‘) != -1 ? arguments[0].split(’ ‘) : arguments[0];
var strTagName = arguments[1] ? arguments[1] : ‘*’;

if(typeof oClassNames == “object”){
for(var i=0; i<oClassNames.length; i++){
arrRegExpClassNames.push(new RegExp(”(^|\\s)” + oClassNames[i].replace(/\-/g, “\\-”) + “(\\s|$)”));
}
}
else{
arrRegExpClassNames.push(new RegExp(”(^|\\s)” + oClassNames.replace(/\-/g, “\\-”) + “(\\s|$)”));
}
var oElement;
var bMatchesAll;
for(var j=0; j<arrElements.length; j++){
oElement = arrElements[j];
bMatchesAll = true;
for(var k=0; k<arrRegExpClassNames.length; k++){
if(!arrRegExpClassNames[k].test(oElement.className)){
bMatchesAll = false;
break;
}
}
if(bMatchesAll){
arrReturnElements.push(oElement);
}
}
return (arrReturnElements)
};