function getElementsByClassName(node,classname){
	if(node.getElementsByClassName){
	//使用现有方法
		return node.getElementsByClassName(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] = elems[i];
			}
		}
			return results;
	}
}