Tracking clicks on AdSense banners on the site side - who did it?

Question

JavaScript

Good news to all, habrochane!
1. Has anyone tried to track clicks (number) on AdSense banners on their site and analyze statistics by comparing them with statistics in the AdSense account?
Is there a difference and is it big? What do you think about making money on ads: what are the alternatives and is it worth investing in it or should you use only direct transactions on your site?
2. What tools did you use?
Thank you all for your help!