Are checking $ SERVER variables server intensive?

How inefficient is this code?

[suga]

I have a sidebar on each page of my site that needs to be wider or narrower depending on where you are on my site. Currently, I have this line of code in the header of each page:

if ($_SERVER[SCRIPT_NAME] == "/index.php")
$width = $homepagewidth;
else if (strstr($_SERVER['SCRIPT_NAME'],"forum"))
$width = $forumwidth;
else
$width = $restofsitewidth;

Is it inefficient to check the SCRIPT_NAME variable on each and every page?

Thanks.

[penders]

As far as I'm aware, checking the $_SERVER superglobal is just like checking any other variable so in that sense I don't think you can really get anymore efficient.

[brotherhood of LAN]

The variables are already present and as penders says, it's just like calling regular variables.

You might be able to optimize the if/else statement though. If you found that 'forum' was getting accessed more frequently than '/index.php' you could put 'forum' at the top of the if/else statement.

[suga]

thank you both!