寫在Html<head>標簽裡面，
復制代碼代碼如下:
<style type="text/CSS">
.x-tree-node-collapsed .x-tree-node-icon {
background:transparent url(web/CSS/images/default/tree/1.gif);
}
.x-tree-node-expanded .x-tree-node-icon {
background:transparent url(web/CSS/images/default/tree/drop-no.gif);
}
.x-tree-node-leaf .x-tree-node-icon{
background:transparent url(web/CSS/images/default/tree/2.gif);
}
</style>