<html><head><meta name="viewport" content="width=device-width, initial-scale=1"></head><body><p>单击按钮以交换 DIV 元素的文本：</p><p><button onclick="myFunction()">点击这里</button></p><div id="myDIV">Hello</div><script>function myFunction() { var x = document.getElementById("myDIV"); if (x.innerHTML === "Hello") { x.innerHTML = "文字互换！"; } else { x.innerHTML = "Hello"; }}</script></body></html>