<html><body><h1>Element 对象</h1><h2>hasAttribute() 方法</h2><button id="myBtn" onclick="myFunction()">按钮</button><p>按钮是否有 onclick 属性：</p><p id="demo"></p><script>const myButton = document.getElementById("myBtn");let answer = myButton.hasAttribute("onclick");document.getElementById("demo").innerHTML = answer;</script></body></html>