<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="zh-tw">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8" />
<title>example for click</title>
</head>
<body>
<button id="btn" onclick="this.innerText='title changed!'">change title</button>
</body>
</html>