Because of the security risks, it is not possible to get Javascript to make a screenshot of a web page. This would allow you to steal credit card info, etc... You can use an active X control or something like that, but the client has to knowingly install it in order for things to work.
In PHP, you can create an image and place it on a web page, but again, you cannot see what is on the client's screen. It has to be done on the server before it is sent to the client.
Here is an example of a library you can use to draw a graph in PHP. http://www.aditus.nu/jpgraph/
You might be able to mimic what jQuery is doing in your script but it will take a shift in your applications design.