how do I center javascript css popup div, no matter what the screen resolution?

Question

I have the following code that opens a new popup window while disabling the background, the problem is that I have to position this so that it\'s 100px from the top (already got

Answer 1

You need to use these styles to make div center:

width:500px; 
left:0;
right:0;
margin:0 auto;