Can I use PHP HTTP_REFERER to display a special message?

I have two domains which are similar,

mysite1.com and mysite2.com

I only have one hosting account and I have the other site forward (through GoDaddy) to the one hosting account.

I want to display a message to users who come to the site from mysite2.com url.

I was thinking I could use PHP HTTP_REFERER to do so.

Is th开发者_StackOverflow社区ere a way to do this?

if(preg_match('@mysite2\.com@i', $_SERVER['HTTP_REFERER'])) {
  print 'Special message!';
}

Actually, HTTP_REFERER will tell you where the user was PREVIOUS to the current page. I think you are looking to use $_SERVER['HTTP_HOST'] instead. This will always yield the domain the user is currently on... mysite1.com or mysite2.com