getting around the undefined index

I have not found a satisfactory way of doing this yet!!!! $text = $_REQUEST['text_size']; if ($text) { echo $text; } I send the $text_size variable to the browser with lines like... <a href="<? $_SERVER['PHP_SELF']; ?>?text_size=small" class="size1" id="one">A</a> When the page initially loads I get a undefined index error as it does not exist but is there a way of wrapping in in a switch statement or funtion so the variable is only used when $_REQUEST['text_size']; actually exists. Ross