function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}

document.getElementsByClassName = function(searchClass,node,tag) {

  if(node == null)node=document;
  var ce = new Array();
  if(tag==null || tag=='*')tag='*';
  var els = new Array();
  if (tag=='*' && document.evaluate){
   var xpr=document.evaluate("//*",document, null, 0, null);
   var t=true;
    while (t=xpr.iterateNext()){
    if(els.push)
     els.push(t);
    else
     els[els.length]=t;
    };
  }
  else
   els = node.getElementsByTagName(tag);
   var elsLen = els.length;
   var pattern = new RegExp("(^|\\s)"+searchClass+"(\\s|$)");
   var i;var j;
   for (i = 0, j = 0; i < elsLen; i++) {
    if ( pattern.test(els[i].className) )
     if (ce.push)
      ce.push(els[i]);
     else
      ce[j++] = els[i];
   }

  return ce;

}