rotate image (onclick, by 90s) possible?

[paul88]

(infos first, server-script: php, client-script:javascript, server-client/client-server protocol:json, my level:newbie)

i have this project where you upload the images first, then you'll see it on the browser, now I want this image to be rotated by 90 degrees everytime i click a certain button(called "rotate 90 degrees")

I really need an expert's advise about this, cause i don't have any idea how to do this kind of "functionality", all i know is that first it will travel from the javascript, then go to the php script using the json string that was passed, then the php will do the rotating, probably the php gd imagerotate function, then it will be passed through back to the javascript again to be displayed and the browser, that's all I know, but I don't know exactly how to do it, and I'm frustrated

Has anyone else come across this problem before?
or any suggestions?