Check if there is a parameter in the URL by PHP

Question

You guys, here’s the deal...
I need to check if in the url there is a parameter (source) and take the value that is being passed by it...

I tested it like this $param = $_GET["source"]; but if there is no parameter in the url, give an error Notice: Undefined index: source.

How do I only get the parameter if it exists?

Answer 1

first check if it exists, so:

if(isset($_GET['source'])) { //existe source?

$param = $_GET['source'];

}
else { //se não existir source, $param terá outro valor

$param = "";

}