How can I add a text box in run time in a position of mouse click on an image map like tagging an image in Facebook?

_ Use javascript onclick event to fire the click event. 

_ Use ajax to call the server side method and pass the x and y mouse coordinates as parameters

_ below an example of getting x and y coordinates of mouse

document.onmousemove = readMouseMove; 

Steps:

1. Add a a click event on either the image or on a transparent layer above it.
2. Add a text box that is hidden by default.
3. In the click event un-hide the text box and set its X and Y (i.e. top and left) co-ordinates based on the current mouse location. You can query the current mouse location.

Note: You may have to use some JavaScript.

Check this out:

http://stackoverflow.com/questions/5782408/is-it-possible-to-create-a-textbox-wherever-the-mouse-is-clicked