How can i drop an image into a textbox inside canvas using html5
===

I am having 4 different images inside my canvas along with a rectangle which it should acts as a textbox.Now i want to drag and drop an image inside the textbox.What i've done sofar is to drag an image inside the canvas but i want to drop that image inside the textbox. For reference http://pastebin.com/dAva6PMC this is all i've done so far please help me out.