<!DOCTYPE html> <html> <body>
<h1>My First Web Page</h1>
<p>My First Paragraph.</p>
<button onclick="myFunction()">点击这里</button>
<script> function myFunction() { document.write("在html文件加载完成后在调用myFunction（）糟糕！文档消失了。"); } </script>
</body> </html>