JavaScript+CSS多级树形展开菜单的代码，本例是应用别人的例子，原来那位老兄是用一般方法写成的无限级折叠菜单，在此先感谢他！后来我就通过了一些简化修改，将原来的例子改成了面向对象的方式，实例中的展开与闭合的小图标可以自己重新添加，从而更好的查看效果。
演示：
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class="keywords">dis</a>play:none;}</style></head><body><ul id=root><li><label><a href=javascript:;>校讯通</a></label><ul class=two><li><label><a href=javascript:;>沈阳市</a></label><ul class=two><li><label><a href=javascript:;>二小</a></label><ul class=two><li><label><a href=javascript:;>二年级</a></label></li><li><label><a href=javascript:;>三年级</a></label><ul class=two><li><label><a href=javascript:;>一班</a></label><ul class=two><li><label><a href=javascript:;>张三</a></label></li><li><label><a href=javascript:;>王五</a></label><ul class=two><li><label><a href=javascript:;>班长</a></label></li><li><label><a href=javascript:;>学习委员</a></label></li></ul></li></ul></li><li><label><a href=javascript:;>实验班</a></label></li></ul></li></ul></li></ul></li><li><label><a href=javascript:;>抚顺市</a></label><ul class=two><li><label><a href=javascript:;>二小</a></label></li><li><label><a href=javascript:;>一中</a></label></li></ul></li></ul></li></ul><script type=text/javascript >/**一般JS<a 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this.nextnode(node.nextSibling);},prevnode:function(node){//寻找上<a href="https://www.jb51.cc/tag/yige/" target="_blank" class="keywords">一个</a>兄弟并剔除空的文本节点if(!node)return ;if(node.nodeType == 1)return node;if(node.prev<a href="https://www.jb51.cc/tag/IoU/" target="_blank" class="keywords">IoU</a>sSibling)return prevnode(node.prev<a href="https://www.jb51.cc/tag/IoU/" target="_blank" class="keywords">IoU</a>sSibling);}}tree = new Tree(root);//实例化应用</script></body></html><div style=text-align:center;margin:30px 0 0 0;><hr style=color:#999;height:1px;>如不能<a href="https://www.jb51.cc/tag/xianshi/" target="_blank" class="keywords">显示</a><a href="https://www.jb51.cc/tag/xiaoguo/" target="_blank" class="keywords">效果</a>，请按Ctrl+F5刷新本页，更多网页<a href="https://www.jb51.cc/tag/daima/" target="_blank" class="keywords">代码</a>：<a href='http://www.wfuyu.com/' target='_blank'>http://www.wfuyu.com/</a></div>提示：可修改后代码再运行!
