How is anonymous IP collected?

[Anonymous]

Thanks for the explanation. Can I do something like this in Javascript just for those IP's I would like to do personalization for? (Or maybe some PHP?)

How to get ip address using javascript or jQuery? - Stack Overflow

We just want to do this for competitors visiting our site; the other anonymous named leads will be targeted in the regular way.

[SanfordWhiteman]

JS alone can't obtain your public IP address, but it can consult an external service to do so. That's what I show how to do in the blog post I linked above.