function nodeClick(el){
        var nodes = document.getElementById("mytree")[0].getElementsByTagName("a");
        for (var node in nodes)
        {
            if(node.id==el.id)
            {
                var url = node.title;
                if(url.indexOf("aspx")>0)
                {
                    document.getElementById("myframe").src = url;    
                }
            }    
        }
    }

------解决方案--------------------
经过消毒验证：
JScript code
<div id="mytree">
  <a href="javascript:void(0)" title="123.aspx">a</a>
  <a href="javascript:void(0)" title="23423.asp">b</a>
  <a href="javascript:void(0)" title="fds.html">c</a>
</div>
<iframe id="myframe" src=""></iframe>

<script language="javascript">
  var nodes = document.getElementById("mytree").getElementsByTagName("a");
  for(var node in nodes){
    nodes[node].onclick=(function(i){
      return function(){
        var title=nodes[i].title;
        if(title.indexOf("aspx")>0){
          document.getElementById("myframe").src = title;
        }
      }
    })(node);
  }
</script>

------解决方案--------------------
(function(fun){
		      fun(document).ready(function(){
		      });
		    })(jQuery);

fun为你要换掉的符号