How to show numerical value of datapoint in image file via onMouseover?

[registering]

Hi all,
I don't know if this can be done with javascript, so please excuse me if I'm posting in the wrong forum.

I'm creating PNG images via PHP that graph data. What I would like is to have a ballon or textfield populated with the numerical value pointed to by the mouse. For example, user scrolls to x,y on my PNG file and somewhere the value -97.008 shows them what they're pointing to. There are generally thousands of data points per PNG file.

Any pointers as to how to get started? I've used bitmaps in HTML before, but only to click on large regions of an image, not specific pixels.

Thanks for any help! :)

[Khalid Ali]

Interesting..you can get the mouse pointer location on the webpage,but about the datapoints,where would that info be stored...
pardon my ignorance about imaging..:-)

[registering]

Good question, I wish I knew. :) That's what I need to find out. I know it can be done, I just don't know what technology is best to use to do it. I could create a bitmap file and with the PHP, create the HTML necessary to dictate x,y mouse coordinates associated with the numerical values, but that would not only lead to HUGE HTML files, since I have 3 graph images per page with thousands of datapoints each, but it would force me to alter my current PHP design. There must be an easier way of doing it....(I hope)