Simple game on JavaScript

.JavaScript. Больше, чем просто сайт!.
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15  
move:
Rules:

You should arrange all numbers in the following form:
	1   2  3  4
	5   6  7  8
	9  10 11 12
	13 14 15
You can move a number on the free field by clicking it with mouse.