How PHP passes data in page jumps and gets the return value

With the development of Internet technology and the widespread application of PHP language, page jump has become one of the commonly used operations in website development. The question that follows is, how to pass data and get the return value during the page jump?

1. Common ways of page jumps

There are three common ways of page jumps on websites: hyperlink jump, form submission and redirection. Each of them has its own characteristics and should be selected according to the specific situation. Different jump methods.

1. Hyperlink jump

Hyperlink jump is one of the simplest jump methods. Just specify the target page to jump to in the link. For example:

<a href="target.php">跳转到目标页面</a>

This kind of jump method can jump between different web pages, but it cannot transfer data during the jump process.

2. Form submission

Form submission is a jump method that can carry data, and is usually used in scenarios such as user registration and login. The form submission process can be performed on the current page or jump to another page. For example:

<form action="target.php" method="POST">
    <p>用户名：<input type="text" name="username"></p>
    <p>密码：<input type="password" name="password"></p>
    <input type="submit" value="提交">
</form>

This jump method can carry the data in the form and pass it to the target page. The target page can obtain the form data through $_POST, but it cannot pass the data back to the current page.

3. Redirect

Redirect is a server-side jump method that can guide the browser to a new page through the HTTP response header. Redirects can carry data, but they need to be passed using URL parameters, for example:

header("Location: target.php?data=value");

This jump method can realize jumps and data transfer between pages, but you need to pay attention to the encoding of Chinese and special characters. At the same time, you need to ensure that the redirection code is executed before the HTML code.

2. Transfer of return value from page jump

In some scenarios, we need to transfer data and obtain the return value during page jump. For example:

• After the user successfully logs in, he will jump to the personal center page to display user information;
• After the user places an order, he will jump to the payment page to obtain the order number and perform payment operations.

Traditional jump methods cannot meet this requirement. The page jump return value can be transferred in the following two ways.

1. Session method

Session is a server-side variable that can share data between different pages or requests. Data can be stored in the Session on the source page, and then the Session data can be read on the target page. For example:

Source page:

session_start();
$_SESSION['data'] = 'test';
header("Location: target.php");

Target page:

session_start();
$data = $_SESSION['data'];
echo $data; // 输出：test

This method can realize the transmission and acquisition of data, but you need to pay attention to the security and validity of the Session to avoid There are data risks caused by session timeout or theft.

2. URL parameter method

URL parameter is a common data transfer method, and data can be transferred to the target page through URL parameters. For example:

Source page:

header("Location: target.php?data=test");

Target page:

$data = $_GET['data'];
echo $data; // 输出：test

This method can realize the transmission and acquisition of data, but you need to pay attention to the length and security of the URL parameters. Avoid data risks caused by URL length restrictions or parameter tampering.

3. Processing of page jump return value

After realizing the transfer of page jump return value, corresponding processing needs to be carried out in the target page. You can determine whether the return value exists by judging the existence and value of the Session or URL parameters, and process the return value accordingly. For example:

Session method:

session_start();
if (isset($_SESSION['data'])) {
    $data = $_SESSION['data'];
    // 处理返回值
    unset($_SESSION['data']); // 清空Session
} else {
    // 返回值不存在
}

URL parameter method:

if (isset($_GET['data']) && !empty($_GET['data'])) {
    $data = $_GET['data'];
    // 处理返回值
} else {
    // 返回值不存在
}

Through the above method, the transmission and processing of page jump return values ​​can be realized, improving the interactivity of the website. and user experience.

To sum up, page jump is one of the commonly used operations in website development. The traditional jump method cannot realize the transmission and processing of the page jump return value. It needs to be implemented through Session or URL parameters. . During use, you need to pay attention to the security and validity of data to avoid data risks.

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