if exist php
if (isset($var)) {
// Code here
}js isset
if (typeof obj.foo !== 'undefined') {
// your code here
}what is isset in php
The isset() function checks whether a variable is set, which means that it has to be declared and is not NULL.
This function returns true if the variable exists and is not NULL, otherwise it returns false.isset
<?php
if (isset($_POST['name'])) $name = $_POST['name'];
else $name = '(enter your name)';
echo <<<_END
<html>
<head>
<title>Test</title>
</head>
<body>
Your name is $name<br />
<form method = 'post' action = 'count.php'>
What's your name?
<input type='text' name='name' />
<input type='submit' />
</form>
</body>
</html>
_END
?>isset
<?php
$a = "3.1416";
if (isset($a)) // la variable $a está definida
unset($a); //ahora ya no está definida
?>Copyright © 2021 Codeinu
Forgot your account's password or having trouble logging into your Account? Don't worry, we'll help you to get back your account. Enter your email address and we'll send you a recovery link to reset your password. If you are experiencing problems resetting your password contact us
