Custom Auto Clicker For Google Chrome

I need an addon or any script that may exclusively run for google chrome or Internet explorer. It should allow me to program the timing of the clicks and loops. It should also show grid or coordinate so I can easily input it. It should allow at least 50 scheduled clicks. I will be using it to 'farm' in an FB game where the screen never changes so auto-clicks look safe. However, it should only run on that browser. Meaning, I can freely use my other browsers without this program intervening. Please let me know if it possible. Thank you!