<html lang="zh"><head> <meta charset="UTF-8"> <title>蝴蝶教程（jc2182.com）</title></head><body><h2 id="demo"></h2><script> // JavaScript可以更改HTML内容 document.getElementById("demo").innerHTML = "欢迎来到蝴蝶教程!"; // JavaScript可以更改HTML样式 document.getElementById("demo").style.fontSize = "25px"; document.getElementById("demo").style.color = "red"; document.getElementById("demo").style.backgroundColor = "yellow"; // JavaScript可以更改HTML属性 document.getElementById("image").src = "images/f1.jpg";</script></body></html>