Tracking Method Comparison :Javascript vs Image vs PHP?

What is the difference between these three methods are there?
What are the advantages and disadvantage of each?

use the Javascript version, if you don’t know the other ones mean

can u give me the link of article for more info?

Have you even tried googling for it? The answers are in the docs. I would agree with Matt though if you dont know what the 3 are go JS.