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>
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<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($y)){
echo 'y is set';
}
/**
* This will NOT echo out 'y is set'
*/isset in php
//with new features in new PHP versions like 7
//you can simplify writing of isset in the following way,
//old way of isset to display name if name variable is not null
echo isset($name) ? $name : "no name"
//new and simple way with null coalescing operator
echo $name ?? "no name"Copyright © 2021 Codeinu
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