Fade in and out in a loop

Fade in and out in a loop

Hi all

I hope its simple enough, I have looked around and can't find exactly what I am after. 

I have a collection of hot spots (divs) on my web page and I need them to fade in and out when viewing the page so they look like they are pulsing so to speak.  When you hover the cursor over one, the pulsing stops for that hotspot only.

Could someone provide some simple example code to help get me started?