convert normal window to modal window?
<p>Is there any way to convert normal window to modal window?</p>

<p>I have a grid with a image column.
As I click the image a window is appearing with the image.(using javascript window.open(...) )</p>

<p>But, as I click a different image in the grid a second window is appearing with respective image.
I dont want the user to be able to do anything else before closing the current window.</p>
