Depending on the URL

[Marshalrusty]

Hello all,
I need to make an if statement which depends on the URL. My site has several domains that all go to the same pages. Now, depending on what domain the people use, certain things need to be different
So

if domai site1()
else if domain site2()
else()

I have no clue how to do this. I would really appreciate some help. Thanks

[devinemke]

check the value of $_SERVER['HTTP_HOST']