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($y)){
echo 'y is set';
}
/**
* This will NOT echo out 'y is set'
*/what is isset in php
The isset() function checks whether a variable is set, which means that it has to be declared and is not NULL.
This function returns true if the variable exists and is not NULL, otherwise it returns false.isset in php
//with new features in new PHP versions like 7
//you can simplify writing of isset in the following way,
//old way of isset to display name if name variable is not null
echo isset($name) ? $name : "no name"
//new and simple way with null coalescing operator
echo $name ?? "no name"Copyright © 2021 Codeinu
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