How to add a pop up using jquery?
<p>My html code:</p>

<pre><code>&lt;form id="room-from" method="post"&gt;
&lt;input id="room" type="text" name="room" /&gt;
&lt;input type="submit" id="save" name="save" /&gt;
&lt;/form&gt;
</code></pre>

<p>when i press the save button if the room text field is empty a pop up should appear at the center of the screen and must say enter a room number.</p>

<p>jquery:</p>

<pre><code>    $("#save").submit(function(){
    if ( $("#room").val() == "")
{

}
    });
</code></pre>

<p>I'm not sure how to do this.</p>

<p>Can anyone please help me out on this.</p>
