abstract：<!DOCTYPE html><html><head> <meta charset="UTF-8" /> <title>全选</title></head><style type="text/css">
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<title>全选</title>
</head>
<style type="text/css">
.box{width:100px;height:250px;border:1px solid #ccc; border-radius:10px;margin:20px auto;text-align:center;padding:5px 10px;}
.box div{border-bottom:1px solid #ccc;padding-bottom:10px;margin-bottom: 8px;}
.box input{margin:8px;}
</style>
<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>
<input type="checkbox" name="item[]">选项7<br>
</div>
</body>
<script>
function checkAll(){
var checkall,item;
checkall = document.getElementById('checkall');
item = document.getElementsByName("item[]");
for(var i=0;i<item.length;i++){
if(checkall.checked){
item[i].checked = true;
}else{
item[i].checked = false;
}
}
}
</script>
</html>
Correcting teacher：天蓬老师Correction time：2019-05-28 15:47:08
Teacher's summary：for(var i=0;i<item.length;i++), 推荐另一种更好的语法
for(var i=0, n = item.length;i<n;i += 1), 这样效率能提升至少10倍