<!DOCTYPE html> <html> <body> <h1>Element 对象</h1> <h2>children 属性</h2> <p>点击“更改”可更改 body 所有子元素的背景。</p> <button onclick="myFunction()">更改</button> <h2>我是 h2 元素</h2> <div>我是 div 元素</div> <span>我是 span 元素</span> <script> function myFunction() { const collection = document.body.children; for (let i = 0; i < collection.length; i++) { collection[i].style.backgroundColor = "red"; } } </script> </body> </html>