<!DOCTYPE html>
<html>
<body>
<h1 id="myH1">如何更改标题的样式</h1>
<p>单击该按钮可更改 H1 元素的样式。</p>
<button onclick="myFunction()">试一试</button>
<script>
function myFunction() {
document.getElementById("myH1").style.color = "red";
}
</script>
</body>
</html>