PHP security question

[dk4210]

Hello Guys,
Could you take a look at my code and see if it is secure enough or if I need to modify it to be more secure?.This is how I call my pages. My link looks something like this http://www.mydomain.com/index.php?content=myscript
and it works great, but I am concerned about the sccurity.. Thanks in advance for your help. Dan


$file = (empty($_GET['content']) ? 'main' : $_GET['content']);
if (file_exists($_SERVER['DOCUMENT_ROOT'] . '' . $file . '.php'))

{
include($file . '.php');
// print "ok"

}else
{
print "Page not available";
}