(PHP 5 >= 5.2.0, PHP 7, PHP 8)
filter_has_var — Checks if variable of specified type exists
input_type
One of INPUT_GET, INPUT_POST,
INPUT_COOKIE, INPUT_SERVER, or
INPUT_ENV.
var_nameName of a variable to check.
Please note that the function does not check the live array, it actually checks the content received by php:<?php$_GET['test'] = 1;echo filter_has_var(INPUT_GET, 'test') ? 'Yes' : 'No';?>would say "No", unless the parameter was actually in the querystring.Also, if the input var is empty, it will say Yes.Through this example i think you can better understand if ( !filter_has_var(INPUT_GET, 'email') ) { echo "Email Not Found"; }else{ echo "Email Found"; } Output localhost/nanhe/test.php?email=1 //Email Found localhost/nanhe/test.php?email //Email Found http://localhost/nanhe/test.php //Email Not FoundConsider on second examplehttp://localhost/nanhe/test.php$_GET['email']="info@nanhe.in";if ( !filter_has_var(INPUT_GET, 'email') ) { echo "Email Not Found"; }else{ echo "Email Found"; }But output will be Email Not Found