全选反选作业
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>全选</title>
<style>
.box{width: 120px;height: 250px;border: 1px solid #000;border-radius: 5px;padding: 5px 10px;margin:60px auto;}
.box div{border-bottom: 1px solid #000;padding-bottom: 10px;margin-bottom: 8px;}
.box input{margin: 8px;}
</style>
</head>
<body>
<div>
<div>
<input type="checkbox" id="checkall" onclick="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>
<input type="checkbox" name="item[]">选项6<br>
</div>
<script type="text/javascript">
function checkall(){
var checkall,item;
checkall=document.getElementById('checkall');
item=document.getElementsByName("item[]");
var i=0;
while(i<item.length){
if(checkall.checked){
item[i].checked=true;
}else{
item[i].checked=false;
}
i++;
}
}
</script>
</body>
</html>