<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>选中的 长度</title>
</head>
<body>
<input type="checkbox" value="1" name="check" checked="checked">
<input type="checkbox" value="2" name="check">
<input type="checkbox" value="3" name="check">
<input type="button" value="你选中的个数" id="btn">
</body>
<script type="text/javascript">
var btn=document.getElementById("btn");
btn.onclick=function(){
var newarr= new Array();
var items=document.getElementsByName('check');
for(i=0;i<items.length;i++){
if(items[i].checked){
newarr.push(items[i].value);
}
}
alert(newarr.length)
}
</script>
</html>
