Using URL Variables

[computer_01]

i have a site and my code looks like this

<?php $comments = $_GET[comments]; ?>

if someone visits the site, at www.domain.com/index.php?comments=yes then the page loads and the word yes is displayed on it, the code for displaying it is

<?php echo $comments ?>

. That works fine. but when there is no ?comments in the url, the page dosen't load, all you see is a blank page. Is there a way to have the page load with or thout the url variable and if the variable is present, have it show it on the page

[piersk]

In this situation, I usually do something like the following:

$url = "pageIwasatbefore.php"
if(@$_GET['comments'] == "")
{
header("Location: $url");
}

The @ is there to stop you getting any errors if there is no ?comments= bit