ExtJS的树(tree)无法在多浏览器下显示,除IE外，如何解决

    <script type="text/javascript">
        Ext.onReady(function(){
        var Tree = Ext.tree;
       //New TreePanel
        var tree = new Tree.TreePanel({
            el:'tree-div',
            autoScroll:true,
            animate:true,
            enableDD:true,
            containerScroll: true,
            loader: new Tree.TreeLoader({
                dataUrl:'<%=basePath %>menus!querySinoInte.action'
            })
        });
    
        //Set Root Node
        var root = new Tree.AsyncTreeNode({
            text: '选择申请对象',
            draggable:false,
            id:'source'
        });
        
        tree.setRootNode(root);
        // render the tree
        tree.render();
        root.expand();
    });
    </script>
 
         
    </script>