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How to solve the problem that php redirect cannot jump
- PHPzOriginal
- 2023-04-03 14:40:281614browse
PHP is a commonly used server-side scripting language that plays an important role in website development. When using PHP to develop a website, the redirect jump function is often used, but sometimes we find that the PHP code cannot implement the redirect jump normally. Why is this? This article will answer this in detail.
- What is redirection jump
Redirection jump refers to the function of automatically redirecting the web page requested by the user to another URL to realize page jump. In PHP, redirection jumps can be implemented through the header() function. The header() function is a built-in function of PHP, used to send native HTTP headers, including status code, Content-Type and other information.
- PHP Redirect Jump Implementation Method
In PHP, there are two ways to implement redirect jump. One is to use the header() function to jump. , the other is to use meta tags to jump.
2.1 Use the header() function to jump
The header() function can realize the redirection jump function and needs to send different HTTP header information according to the situation.
The sample code is as follows:
<?php
header("Location: http://www.example.com/");
exit();
?>
In the above code, the header() function passes the redirected URL in the form of a parameter, such as "http://www.example.com/", and then Call the exit() function to stop the execution of the current script to ensure that the redirection takes effect.
It should be noted that no information, including HTML tags, spaces, newlines, etc., can be output to the client before using the header() function to jump.
2.2 Use meta tags to jump
In addition to using the header() function to jump, you can also use the meta tag in HTML to jump.
The sample code is as follows:
<!DOCTYPE html> <html> <head> <meta http-equiv="refresh" content="0;URL='http://www.example.com/'" /> </head> <body> </body> </html>
In the above code, the meta tag uses the content attribute to specify the URL to jump to, and sets a timer. When the timer value is 0, it means an immediate jump. .
It should be noted that when using meta tags to jump, the page will stay for a period of time before jumping to the specified URL, which may lead to poor user experience.
- Causes of problems with PHP redirection jump
PHP redirection jump sometimes fails to jump, which is mainly due to the following reasons ：
3.1 Information has been output to the client previously
When using the header() function to jump, you must ensure that no information is output to the client before calling the header() function, otherwise Will cause redirection to fail.
The sample code is as follows:
<!DOCTYPE html>
<html>
<head>
<?php
echo "Hello World!";
header("Location: http://www.example.com/");
exit();
?>
</head>
<body>
</body>
</html>
In the above code, the echo statement is first used to output the "Hello World!" text to the client. When the header() function is called to jump, since it has already been The client output information, causing the redirection to fail.
3.2 Wrong URL
If the redirected URL is incorrect, the redirection will fail. At this time, you need to check whether the URL is correct and whether it contains the correct protocol and host name.
The sample code is as follows:
<?php
header("Location: example.com");
exit();
?>
In the above code, the redirected URL does not specify the protocol and host name, causing the redirection to fail.
- Summary and Suggestions
PHP redirect jump is a very common function, and you need to pay attention to some details during use. First of all, when calling the header() function to jump, you need to ensure that no information is output to the client before the call; secondly, when setting the jump URL, you need to ensure that the URL is correct, including protocol, host name and other information. . Finally, it is recommended to use the header() function for jumping, because it is more flexible and reliable than meta tag jumping.
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