I have a URL which i pass parameters into

> 
> example/success.php?id=link1
> 
> 
> 

I use php to grab it

```
$slide = ($_GET["id"]);

```

then an if statement to display content based on parameter

```
<?php  if($slide == 'link1') { ?>
   //content
 } ?>

```

Just need to know in PHP how to say, if the url param exists grab it and do the if function, if it doesn't exist do nothing.

Thanks Guys