gerador de código PHP

		<form method="post">
			<input type="submit" value="Comprar"/>
		</form>
		<br/>
		<h2>Código do cupom</h2>
		<br/>
		<?php echo generateRandomString(); ?>
		

		<?php 

			function generateRandomString($length = 10) {

			    $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
			    $charactersLength = strlen($characters);
			    $randomString = '';
			    for ($i = 0; $i < $length; $i++) {
			        $randomString .= $characters[rand(0, $charactersLength - 1)];
			    }
			    return $randomString;
			}

		?>