function TreeMenu(node,id)
{
 var sibling = document.getElementById(id);

 if (sibling.style.display == 'none')
 {
  if (node.childNodes.length > 0)
  {
   if (node.childNodes[0].tagName == "IMG")
   {
    node.childNodes[0].src = "images/j.gif"; //替换为展开时的图片
   }
  }

  sibling.style.display = '';
 }
 else
 {
  if (node.childNodes.length > 0)
  {
   if (node.childNodes[0].tagName == "IMG")
   {
    node.childNodes[0].src = "images/i_plus.gif";  //替换为收起时的图片
   }
  }
  sibling.style.display = 'none';
 }
}