全选的练习作业
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>全选框</title>
<script type="text/javascript">
function checkAll() {
// var checkall,item;
var x , y;
x=document.getElementById('checkall')
item=document.getElementsByName("item[]")
for(var i=0;i<item.length;i++) {
if(x.checked){
item[i].checked=true;
}else{
item[i].checked=false;
}
}
}
</script>
</head>
<body>
<div>
<div><input type="checkbox" id="checkall" onclick="checkAll()"><label for="checkall">全选</label></div>
<div>
<input type="checkbox" name="item[]">1
<input type="checkbox" name="item[]">2
<input type="checkbox" name="item[]">3
<input type="checkbox" name="item[]">4
</div>
</div>
</body>
</html>