javascript：getElementsByClass

Question

Im looking to do something simple and the site is not heavy with js so im not using a js framework for this.

I am trying to add event click listener, I am trying to get element by class. I found the following function + others that I have tried but for some reason none of them are finding the elements.

function getElementsByClass( searchClass, domNode, tagName) { 
    if (domNode == null) domNode = document;
    if (tagName == null) tagName = '*';
    var el = new Array();
    var tags = domNode.getElementsByTagName(tagName);
    var tcl = " "+searchClass+" ";
    for(i=0,j=0; i<tags.length; i++) { 
        var test = " " + tags[i].className + " ";
        if (test.indexOf(tcl) != -1) 
            el[j++] = tags[i];
    } 
    return el;
}
var els = getElementsByClass("wow");
alert(els.length);

i have a couple of divs with the class wow, testing but I keep getting 0.

Answer 1

Assuming your function works properly, do it when the DOM is ready or on window load. Or call it before the end body tag.

DEMO : http://jsfiddle.net/rXApk/

Answer 2

The class attribute takes a space separated list of class names, not a comma separated list.

Your test won't match wow, as it looks for wow .