JQuery Mobile 弹出式登录框的实现方法

<a href="#login" data-rel="popup" data-position-to="window" data-role="button">Login</a> 
  <div data-role="popup" id="login" data-theme="a"> 
    <form style="padding:10px 20px;"> 
      <h3>Please sign in</h3> 
      <label for="un" class="ui-hidden-accessible">Username:</label> 
      <input type="js" name="user" id="un" placeholder="username" /> 
      <label for="pw" class="ui-hidden-accessible">Password:</label> 
      <input type="password" name="pass" id="pw" placeholder="password" /> 
      <button type="submit" data-theme="b">Sign in</button> 
    </form> 
  </div>