<html><body>电子邮件：<input type="email" id="myEmail"><p>单击按钮可将电子邮件字段设置为只读。</p><p><b>提示：</b>如需查看效果，请尝试在单击按钮前后在电子邮件字段中键入内容。</p><button onclick="myFunction()">试一试</button><p id="demo"></p><script>function myFunction() { document.getElementById("myEmail").readOnly = true;}</script></body></html>