getElementByClassName

function getElementByClassName(node,classname){
  if(node.getElementByClassName){
    return node.getElementByClassName(classname)
   }else{
    var results = new Array()
    var elems = node.getElementsByTagName('*')
    for (var i=0;i<elems.length;i++){
      if(elems[i].className.indexOf(classname) != -1){
        results[results.length]=elem[i]
      }
    }
    return results
}