全选框的实现
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>checkbox</title>
<style type="text/css">
.box{
width:120px;
height:250px;
border:1px solid #ccc;
border-radius: 5px;
padding:5px 10px;
margin:20px auto;
}
</style>
</head>
<body>
<script type="text/javascript">
function checkall(){
var checkall,item;
checkall=document.getElementById('checkall');
item=document.getElementsByName('item[]');
for(var i=0;i<item.length;i++){
if(chechkall.checked){
item[i].checked=true;
}else{
item[i].checked=false;
}
}
}
</script>
<div>
<div>
<input type="checkbox" name="" id="checkall"><label for="checkall">全选</label>
</div>
<input type="checkbox" name="item[]">选项1<br>
<input type="checkbox" name="item[]">选项2<br>
<input type="checkbox" name="item[]">选项3<br>
<input type="checkbox" name="item[]">选项4<br>
<input type="checkbox" name="item[]">选项5<br>
</div>
</body>
</html>