Dtree jsp页面显示不了

-------jsp页面-------------------创建树的实例
<script>
tree=new dTree("tree");
</script>
<jsp:useBean id="trees" class="com.daos.MenuDao"></jsp:useBean>

<c:forEach items="${trees.memucontent}" var="tree">
<script>
tree.add(${tree.nodeId},${tree.parentId},'${tree.nodeName}','ser?method=checkinfo&id=${tree.nodeId}','','right');
</script>
</c:forEach>

<script>
document.write(tree);
</script>
------------------
我查看源文件的时候里面是有数据的，但就是字浏览器里显示不了，IE9，火狐都试过了，没用！

---------------源文件代码--------------<!-- 引用树的文件 -->
<link rel="stylesheet" href="dtree.css" type="text/css"></link>
<script type="text/javascript" src="dtree.js">
</script>


创建树的实例
<script>
tree=new dTree("tree");
</script>



<script>
tree.add(1,1,'bb','ser?method=checkinfo&id=1','','right');
</script>

<script>
tree.add(2,2,'XX','ser?method=checkinfo&id=2','','right');
</script>

<script>
tree.add(3,1,'SS','ser?method=checkinfo&id=3','','right');
</script>

<script>
tree.add(4,2,'2','ser?method=checkinfo&id=4','','right');
</script>

<script>
tree.add(5,2,'2','ser?method=checkinfo&id=5','','right');
</script>

<script>
tree.add(1,1,'1','ser?method=checkinfo&id=1','','right');
</script>

<script>
tree.add(1,,'1','ser?method=checkinfo&id=1','','right');
</script>

<script>
tree.add(1,,'1','ser?method=checkinfo&id=1','','right');
</script>

<script>
tree.add(1,,'1','ser?method=checkinfo&id=1','','right');
</script>

<script>
tree.add(1,,'1','ser?method=checkinfo&id=1','','right');
</script>

<script>
tree.add(1,,'1','ser?method=checkinfo&id=1','','right');
</script>


<script>
document.write(tree);
</script>