<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>测试</title>
<style>
body { background: #FF0000; }
</style>
</head>
<body>
<h1>如果看到红色背景和这行字，说明运行成功！</h1>
<script>
alert("JavaScript 运行正常！");
</script>
</body>
</html>
JSRUN 用代码说话
