javascript,二级TreeView中点选某结点(第一级)时,其它非点选结点(第一级)均闭合

<script language="javascript">
  function setExpan(){
     var indexid;
     var i;
      indexid=TreeView1.clickedNodeIndex;
     var NodeArray=new Array();
     var NodeCount=new Array();
     NodeArray=TreeView1.getTreeNode(indexid).getChildren();
           NodeCount=TreeView1.getChildren();
      if (indexid!=null) {
       if (TreeView1.getTreeNode(indexid).getAttribute('Expanded'))
       { 
       TreeView1.getTreeNode(indexid).setAttribute('Expanded','false');
       }
       else
       { 
       TreeView1.getTreeNode(indexid).setAttribute('Expanded','true');
       }
    //将所有非选中选项合闭，同时满足点击末级不合闭条件 
   for (i = 0; i <NodeCount.length ; i ++){
  
              if (i .toString()!=indexid && NodeArray.length !=0){
    TreeView1.getTreeNode(i .toString()).setAttribute('Expanded','False');}
  }     
          } //if
        }//function
  </script> 

Page_load:
TreeView1.Attributes.Add("onclick", "setExpan();")