PHP - Data after "?" in URL displays different information
<p>I know the title isn't very clear.  I'm new to PHP, so there might be name for this kind of thing, I'll try to explain as best as I can.  Sometimes in a URL, when using PHP, there will be a question mark, followed by data.  I'm sorry, I know this is very noobish, but I'm not sure what it's called to look for a tutorial or anything.  Here is what I mean:</p>

<p><a href="http://www.website.com/error%5Fmessages.php?error%5Fid=0" rel="nofollow">http://www.website.com/error%5Fmessages.php?error%5Fid=0</a></p>

<p>How do you configure it to display different text depending on what the number is (in this example it's a number)</p>

<p>Could somebody please tell me what this is called and how I could do this?  I've been working with PHP for a couple days and I'm lost.  Thank you so very much for understanding that I am very new at this.</p>
