function getElementsByClass(searchClass,node,tag) {
    var classElements = new Array();
    if(node == null) node = document;
    if(tag == null) tag = '*';

    var els = node.getElementsByTagName(tag);
    var elsLen = els.length;
    var pattern = new RegExp("(^|\\s)"+searchClass+"(\\s|$)");

    for(i = 0, j = 0; i < elsLen; i++) {
        if (pattern.test(els[i].className) ) {
            classElements[j] = els[i];
            j++;
        }
    }

    return classElements;
}