How to create a small box above selected text ( double click to select it )
<p>I try to write a dictionary extension for Google Chrome. Now, I want to pop out a small box when I double click to select text . How can I implement it :)
Or like this one ( Fastest Chrome ). They're written in javascript.</p>

<p><img src="http://img130.imageshack.us/img130/9721/abcjq.jpg" alt="alt text">
Thanks so much ! </p>
