I am trying to achieve a certain effect where a user clicks on a link that opens a popup window using AJAX. When that happens, I want the rest of the browser window to dim to emphasize the current window. Then, once the popup is closed, the window is no longer gray.

I'm not looking for someone to do this for me, I really need to know what this is called right now. I can't even research it because I don't know the name. Please help me out.

Are you talking about a thing for images?

You could use Lightbox 2 to create that effect.

Great! that was exactly what I was looking for. thank you!