x
 
<!DOCTYPE html>
<html>
<body>
<h1>Document 对象</h1>
<h2>implementation 属性</h2>
<p>该文档是否具有 DOM 1.0 特性?</p>
<p id="demo"></p>
<script>
let answer = document.implementation.hasFeature("DOM", "1.0");
document.getElementById("demo").innerHTML = answer;
</script>
</body>
</html>