<html>
<body>
E-mail: <input type="email" id="myEmail">
<p>点击按钮设置 email 字段为只读。</p>
<p><strong>提示：</strong> 为了查看效果，可以在点击按钮前后编辑 email 字段。</p>
<button onclick="myFunction()">点我</button>
<p id="demo"></p>
<script>
function myFunction() {
document.getElementById("myEmail").readOnly = true;
}
</script>
</body>
</html>