isset function in php
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<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<form action="" method="post">
<h1>ISSET Demo</h1>
<input type="submit" value="Click here" name="btn1">
</form>
</body>
</html>
<?php
if(isset($_POST['btn1']))
{
echo "button was set!";
}
?>isset in php
/**
* Returns a bool (true or false)
*/
isset($x);
/**
* Examples
*/
$x = 'myValue';
if(isset($x)){
echo 'x is set';
}
/**
* this will echo out 'x is set'
*/
$x = null;
if(isset($x)){
echo 'x is set';
}
/**
* This will NOT echo out 'x is set'
*/
if(isset($y)){
echo 'y is set';
}
/**
* This will NOT echo out 'y is set'
*/isset in php
$age = 0;
// Evaluates as true because $age is set
if (isset($age)) {
echo '$age is set even though it is empty';
}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.Copyright © 2021 Codeinu
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