Checkbox in PHP

Let's now learn how to work with checkbox in PHP. Let's create such a checkbox in our form:

<form action="" method="GET">
	<input type="checkbox" name="flag">
	<input name="text">
	<input type="submit">
</form>

After submitting the form, $_GET of the checkbox will contain the string 'on' if the checkbox was checked and null if not:

<?php
	var_dump($_GET['flag']); // 'on' or null
?>

Let's display something on the screen depending on whether the checkbox was checked or not:

<?php
	if (!empty($_GET)) { // if the form was submitted
		if (isset($_GET['flag'])) { // if the checkbox is checked
			echo 'checked';
		} else {
			echo 'not checked';
		}
	}
?>

Create a form with an input and a checkbox. Using the input, ask the user for their name. After submitting the form, if the checkbox was checked, greet the user, and if it was not checked - say goodbye.