<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>getElement获取标签标识</title>
</head>
<body>
<label>爱好：</label>
<input type="checkbox" value="篮球" id="aihao" name="aihao" class="aihao" />篮球
<input type="checkbox" value="唱歌" id="aihao" name="aihao" class="aihao" />唱歌
<input type="checkbox" value="抽烟" id="aihao" name="aihao" class="aihao" />抽烟
<input type="checkbox" value="吃饭" id="aihao" name="aihao" class="aihao" />吃饭
<input type="checkbox" value="吃鸡" id="aihao" name="aihao" class="aihao" />吃鸡
<input type="checkbox" value="联盟" id="aihao" name="aihao" class="aihao" />联盟
<button οnclick="aihao();">有多少爱好</button>
<script type="text/javascript">
function aihao(){
//根据class获取标签标识
var str=document.getElementsByClassName("aihao");
//返回获取到的数组长度
alert(str.length);
}
</script>
</body>
</html>
