ASP ImageButton OnClick coordinates

Question

I have an ASP.Net ImageButton in .Net 3.5. It's a large image, 450x700 that users can click on. On the server side, the OnClick event handler does some stuff based on the coordinates that the user clicks.

It's a basic map, just a single static image, that users can click on.

It works great, except when, in IE, the user is at a zoom level other than 100%. In that case, it passes the actual pixel coordinates of the click, meaning that I get a point that's somewhere on a line between the origin and the point of the click.

I looked at doing something like actualX = clickedX * image.Width / 450, but the image size properties don't change when the image is zoomed, image.Width always stays at 450.

Short of a bunch of Javascript black magic that I'd rather avoid is there any way to find the original image coordinates that correspond to the point that is clicked?

Answer 1

It is not possible for the server to determine the zoom level of the browser without Javascript.

This sounds like a bug in IE. Zooming in on the page should be completely transparent to the server. You should report this to Microsoft.