20c03-2.php

介绍PHP5的给类型函数应用

<?php
// Start the PHP session
session_start();

// If this page was submitted back to itself:
if (count($_POST)) {
	// Ensure that a session captcha was set:
	if (isset($_SESSION['captcha'])) {
		// See if this one matches the submitted value:
		if ($_SESSION['captcha'] === strtoupper($_POST['check'])) {
			// We have a valid match!  The most important thing to do now 
			// is destroy the previous captcha entry so that they can't 
			// just resubmit this same form again!
			unset($_SESSION['captcha']);
			
			// Now the script should do it's action, redirect, etc.
			// For now, we are just going to say congratz
			echo "<p>Congratulations, you typed it in correctly!</p>\n";
		} else {
			// Bad attempt -- Let them know it was wrong, this page will
			// then continue and give them a new one anyway.
			echo "<p>Sorry, that wasn't it, try again!</p>\n";
		}
	} else {
		// The session captcha variable wasn't set, this means that someone
		// submitted successfully once, then tried to spam us with the same
		// session information.
		echo "<p>Sorry, no spamming aloud!  Go away!  Shoo!</p>\n";
	}
}
?>
<form action="<?= $_SERVER['PHP_SELF'] ?>" method="post">
Please enter the text that you see in the following graphic:<br />
<!-- <img src="captcha.php" /><br /> -->
<img src="20c03-1.php" /><br />
<input name="check" type="text"><br />
<input name="Submit" type="submit">
</form>