<!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>js复选框（checkbox）</title>
<link href="css/lanrenzhijia.css" type="text/css" rel="stylesheet" />
<script type="text/javascript">
window.onload = function ()
{
var oA = document.getElementsByTagName("a")[0];
var oInput = document.getElementsByTagName("input");
var oLabel = document.getElementsByTagName("label")[0];
var isCheckAll = function ()
{
for (var i = 1, n = 0; i < oInput.length; i++)
{
oInput[i].checked && n++
}
oInput[0].checked = n == oInput.length - 1;
oLabel.innerHTML = oInput[0].checked ? "全不选" : "全选"
};
//全选/全不选
oInput[0].onclick = function ()
{
for (var i = 1; i < oInput.length; i++)
{
oInput[i].checked = this.checked
}
isCheckAll()
};
//反选
oA.onclick = function ()
{
for (var i = 1; i < oInput.length; i++)
{
oInput[i].checked = !oInput[i].checked
}
isCheckAll()
};
//根据复选个数更新全选框状态
for (var i = 1; i < oInput.length; i++)
{
oInput[i].onclick = function ()
{
isCheckAll()
}
}
}
</script>
</head>
<body>
<dl>
<dt><input type="checkbox" id="checkAll" /><label>全选</label><a href="javascript:;">反选</a></dt>
<dd>
<p><input type="checkbox" name="item" /><label>选项（一）</label></p>
<p><input type="checkbox" name="item" /><label>选项（二）</label></p>
<p><input type="checkbox" name="item" /><label>选项（三）</label></p>
<p><input type="checkbox" name="item" /><label>选项（四）</label></p>
<p><input type="checkbox" name="item" /><label>选项（五）</label></p>
<p><input type="checkbox" name="item" /><label>选项（六）</label></p>
<p><input type="checkbox" name="item" /><label>选项（七）</label></p>
<p><input type="checkbox" name="item" /><label>选项（八）</label></p>
<p><input type="checkbox" name="item" /><label>选项（九）</label></p>
<p><input type="checkbox" name="item" /><label>选项（十）</label></p>
</dd>
</dl>
<center>1、切换全选/全不选文字；2、根据选中个数更新全选框状态；</center>
</body>
</html>
