用jquerytree和jquery做树的实例（第一次用这个，很强大，本次例子不是很好，但效果出来了）

<script language="javascript" type="text/javascript" src="jquery-1.4.2.js"></script>
<script language="javascript" type="text/javascript" src="jquery.ztree-2.6.js"></script>
<link rel="stylesheet" type="text/css" href="zTreeStyle.css" />


<ul id="tree" class="tree" style="width:300px; overflow:auto;"></ul>


<input id="kk" type="button" value="获取节点值" onclick="ff()"/><br>
<input id="cch" type="button" value="改变树" onclick="cch()"/><br>
<textarea id="ta" cols="30" rows="5"></textarea>

<script language="javascript" type="text/javascript">
//alert($("kk").val());
var setting = {
//    showLine: true,
    checkable: true,
checkStyle:"checkbox",

	nameCol : "ename",//不写，默认name
//nodesCol : "child",//不写，默认nodes


	isSimpleData : true,
    rootPID : -1,
    treeNodeKey : "id",
    treeNodeParentKey : "pId"


};

var zTreeNodes = [
    {"id":1, "ename":"全国", "nodes":[
      {"id":11, "ename":"北京大区", "nodes":[
        {"id":111, "ename":"北京中心"}
      ]},
      {"id":12, "ename":"上海大区"}
    ]}

];

var zTreeNodes2 = [
    {"id":1, "pId":0, "ename":"全国"},
    {"id":11, "pId":1, "ename":"河北大区 ",click :"ff2('11')"},
    {"id":12, "pId":1, "ename":"山东大区",click : "ff2('12')" },
    {"id":111, "pId":11, "ename":"石家庄中心",click : "ff2('111')" }
];

var zTree = $("#tree").zTree(setting, zTreeNodes2);


function ff2(nn){
   alert(nn);
}

function cch(){
   var zTree = $("#tree").zTree(setting, zTreeNodes);
}

</script>