Doorknob Doorknob - 6 months ago 25
PHP Question

How to verify if $_GET exists?

So, I have some PHP code that looks a bit like this:

<body>
The ID is

<?php
echo $_GET["id"] . "!";
?>

</body>


Now, when I pass an ID like
http://localhost/myphp.php?id=26
it works alright, but if there is no ID like just
http://localhost/myphp.php
then it outputs:

The ID is
Notice: Undefined index: id in C:\xampp\htdocs\myphp.php on line 9
!


I have searched for a way to fix this but I cannot find any way to check if a URL variable exists. I know there must be a way though.

Answer

You can use isset function:

if(isset($_GET['id'])) {
    // id index exists
}

You may also want to check what's inside, e.g. you can use is_int function to check if variable contains integer etc

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