问题
I am experimenting with cookies and i am doing this quick example,
<html>
<head>
<meta charset="UTF-8">
<title>Cookies</title>
</head>
<body>
<!-- Start of FORM -->
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>">
Username: <input type="text" name="username"><br>
<input type="submit" name="submit" value="Submit">
</form>
<!-- End of FORM -->
<hr>
<?php
if (isset($_POST['username'] )) {
setcookie('username', $_POST['username'], time() + 1000, '/');
if(isset($_COOKIE['username'])){
echo "Hello " . $_COOKIE['username'];
unset($_COOKIE['username']);
}
}
?>
</body>
It works but i have to click the submit button twice for my message to display, why is that?
回答1:
From the PHP Docs..
Cookies will not become visible until the next loading of a page that the cookie should be visible for. To test if a cookie was successfully set, check for the cookie on a next loading page before the cookie expires.
So whilst you clicked the button the second time, the actual load was in effect and you were able to see it(the cookie).
来源：https://stackoverflow.com/questions/23533456/simple-php-cookie