phpurlurl-parameters

PHP check if url parameter exists

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.

Solution

  • Use isset().

    if (isset($_GET["id"])) {
    // do something when a parameter exists
}

    You can check the existence and equality in a single condition too

    if (isset($_GET["id"]) && $_GET["id"] === 'link1') {
    // exists and equal to link1
}

    However, it would be more convenient to define a variable first, using ?? shorthand, and then use it in a condition

    $slide = $_GET["id"] ?? '';
...
if($slide === 'link1') {
    // equal to link1
}

    Here, an empty string is used as a default value in case parameter is not defined. You can change it to any other value.