今天用MzTreeView1.0时碰到树默认展开的问题，但怎以都实不了，求救？？

function focusTree(arrSourceIndex)
{
var arr = arrSourceIndex.split("_");
for(var i=0;i<arr.length-1;i++)
expandNode(arr[i]+"_"+arr[i+1]);
}
function expandNode(sourceIndex)
{
try
{
var expandId =  tree.getAttribute(tree.nodes[sourceIndex],"index");
tree.focusClientNode(expandId);
if (!tree.node[expandId].isExpand)
tree.newExpand(expandId);
}
catch(e){}
}
focusTree("0_1_320");