不废话，上代码，要下载的在文章末尾有连接
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<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>
<script>
window.onload=function()
{
var aCh=div1.getElementsByTagName('input');
btn1.onclick=function()
{
//aCh[0].checked=true;
for( var i=0;i<aCh.length;i++){
aCh[i].checked=true;
};
};
btn2.onclick=function()
{
//aCh[0].checked=true;
for( var i=0;i<aCh.length;i++){
aCh[i].checked=false;
};
};
btn3.onclick=function()
{
//aCh[0].checked=true;
for( var i=0;i<aCh.length;i++){
if(aCh[i].checked==true){
aCh[i].checked=false;
}else{
aCh[i].checked=true;
}
};
};
};
</script>
</head>
<body>
<input id="btn1" type="button" value="全选" />
<input id="btn2" type="button" value="不选" />
<input id="btn3" type="button" value="反选" />
<div id="div1">
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
<input type="checkbox" /> <br />
</div>
</body>
</html>
http://download.csdn.net/detail/qq_25824243/9873810