How to check for $_GET value and set variable as that value - noob please help!

Hey guys I'm a php noob who's inherited this site and can't figure out how to check if the url has a variable in it, then set that variable as something else (sorry if the jargon's wrong)

function adExtNo($defaultExt = '1004'){
	if(isset($_COOKIE[__FSCOOKIE_PRINT_EXT])){ //Detect custom print media ad ext number
		$adCookie = $_COOKIE[__FSCOOKIE_PRINT_EXT];
		return $adCookie;
	}else{ //Else detect ppc ad ext number
		if(isset($_COOKIE[__FSCOOKIE_PPC_EXT])){
				$adCookie = $_COOKIE[__FSCOOKIE_PPC_EXT];
				return $adCookie;
	}else{ //Else detect ppc ad ext number in url
		if(isset($_GET[ppc_ext])){
				$adCookie = $_GET[ppc_ext];
				return $adCookie;
		}else{ //Else just set ext number to web default
				return $defaultExt;
		}
	}
}

PHP:

Currently the code checks for a variable in a cookie then sets $adCookie as that value (I believe). If there's no cookie value then I want it to get the value from the tagged url, and if the url isn't tagged then defaultExt.

I've been trying to add the second }else{ statement to detect a variable in the URL (i.e. url.com/?ppc_ext=1234) then if it exists set $adCookie to that value, else return $defaultExt.

does anyone know how to do this?
Thanks for any help.

 

I haven't tested this but give this a try,

function adExtNo($defaultExt = '1004'){
	if(isset($_COOKIE[__FSCOOKIE_PRINT_EXT])) {
		//Detect custom print media ad ext number
		$adCookie = $_COOKIE[__FSCOOKIE_PRINT_EXT];
		return $adCookie;
	}elseif(isset($_COOKIE[__FSCOOKIE_PPC_EXT])) {
		//Else detect ppc ad ext number
		$adCookie = $_COOKIE[__FSCOOKIE_PPC_EXT];
		return $adCookie;
	}elseif(isset($_GET[ppc_ext])) {
		//Else detect ppc ad ext number in url
		$adCookie = $_GET[ppc_ext];
		return $adCookie;
	}else{
		//Else just set ext number to web default
		return $defaultExt;
	}
}

PHP:

 

that works perfectly.

Thanks so much for the help. I was struggling there.

I'll definitely keep your contact details for projects in the future.