<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
ul { list-style:none; }
</style>
<script type="text/javascript">
window.onload = function() {
var obj = document.getElementById('demo').getElementsByTagName('input');
for (var i = 0; i < obj.length; i ++) {
obj[i].onclick = function() {
//查找并选择/取消选择所有子项
var childrenObj = this.parentNode.getElementsByTagName('ul');
if (childrenObj.length > 0) {
for (var j = 0; j < childrenObj.length; j ++) {
var o = childrenObj[j].getElementsByTagName('input');
for (var k = 0; k < o.length; k ++) o[k].checked = this.checked;
}
}
//递归方法检查并设置父选项选择状态
checkParent(this);
}
}
}
function checkParent(obj) {
var parentObj = obj.parentNode.parentNode;
if (parentObj.id != 'demo') {
parentObj = parentObj.parentNode;
var FLAG = true; //标志位，true表示父级选项的所有子选项都是选中的，初始值为true，假设全部为选中
var o = parentObj.getElementsByTagName('input');
for (var i = 1; i < o.length; i ++) {
if (!o[i].checked) {
FLAG = false;
break;
}
}
if (FLAG) o[0].checked = true;
else o[0].checked = false;
if (parentObj.parentNode.parentNode.id != 'demo') checkParent(o[0]);
}
}
</script>
</head>
<body>
<form id="weaver" name="frmmain" method="post">
<ul id="demo">
<li><input type="checkbox" />系统使用
<ul>
<li><input type="checkbox" />系统使用规范</li>
<li><input type="checkbox" checked/>系统功能介绍
<ul>
<li><input type="checkbox" checked/>三级选项1
<ul>
<li><input type="checkbox" />四级选项1</li>
</ul>
</li>
<li><input type="checkbox" checked/>三级选项2</li>
</ul>
</li>
</ul>
</li>
<li><input type="checkbox" />会议资料
<ul>
<li><input type="checkbox" />会议资料</li>
</ul>
</li>
</ul>
</form>
</body>
</html>
