Ie和谷歌都试过了，都不行，
<head>
<script type="text/javascript">
function checkall(){
var qwe = document.getElementsByName("aihao");
for(var i = 0;i < qwe.length;i++){
qwe[i].checked = true;
}
}
</script>
</head>
<body>
<form>
兴趣爱好：
<input type="checkbox" name="aihao" value="c" checked="checked" />c++
<input type="checkbox" name="aihao" value="java" />java
<input type="checkbox" name="aihao" value="javaweb" />javaweb
<input type="checkbox" name="aihao" value="javascript" />javascript
<button onclick="checkall()">全选</button>
<button onclick="checkno()">全不选</button>
<button onclick="checkres()">反选</button>
</form>
</body>
