I am trying to create a website which simply allows you to upload a pdf image file and then zoom in and out of it. The only trick is that I want the zoom function to work as a window, where you use the mouse to draw a rectangle over the picture and the image zooms into the rectangle. Then, I want to be able to zoom back out just by pressing CTRL-Z or something like that. I can't seem to find any code out there that can help me to do this. Does anyone have a lead?