​x
 
<!DOCTYPE html>
<html>
<body>
​
<h1>Window 对象</h1>
​
<h2>frameElement 属性</h2>
​
<p>这个窗口在框架中吗？</p>
<p id="demo"></p>
​
<script>
let answer = "否";
​
if (window.frameElement) {
  answer = "是";
}
​
document.getElementById("demo").innerHTML = answer;
</script>
​
</body>
</html>
​