HTML5 placeholder和自定义下拉在一起的时候
代码：
HTML代码：
<label for="email">邮箱:</label>
<input id="email" type="email" placeholder="zhangxinxu@zhangxinxu.com" autocomplete="off" size="26" />
<label for="email">邮箱:</label>
<input id="email" type="email" placeholder="zhangxinxu@zhangxinxu.com" autocomplete="off" size="26" />