Getting the src on the image on the button

Question

Hi,
i am developing chess game in HTML with javascript.
i have created all the boxes as buttons with images on it.
Now what i want is i need the src of the image on a particular button i click..please help me.

For Ex:
I clicked on the A5 box on chess board and it has image of white pawn,now what i want is the src of the image present on A5 buton. please reply me...