Use PHP$_SERVER['HTTP_REFERER'] to get the page source address

When browsing web pages on the Internet, we often see some jump links. When we click on these links, we will jump to another web page or website. So, how do we know which website or webpage we are redirected from? At this time, we need to use an important PHP variable-$_SERVER['HTTP_REFERER'].

$_SERVER['HTTP_REFERER'] variable is a variable used to obtain the source address of the HTTP request. That is to say, when a web page jumps to another web page, the jumped page information will be stored in the HTTP header, and $_SERVER['HTTP_REFERER'] is used to obtain this information. Specifically, there will be a Referer attribute in the HTTP header, which is used to indicate the source address of the request. We can obtain its value through the $_SERVER['HTTP_REFERER'] variable.

$_SERVER is an array containing server information, and the variable $_SERVER['HTTP_REFERER'] is one of the elements. It contains the source address of the current request. If the current request does not jump from other web pages If it is turned over, its value will be empty.

After understanding the role and usage of $_SERVER['HTTP_REFERER'], we can use it to implement some interesting functions.

For example, in the statistical function of our website, we can use $_SERVER['HTTP_REFERER'] to analyze the traffic source of our website. By analyzing the source of visits, we can know which web pages or websites promote our website, so as to make some optimization improvements.

We can also use $_SERVER['HTTP_REFERER'] to implement some security controls. For example, there is a form in our website. If we want only users who jump from our website to submit the form, then we can judge the value of $_SERVER['HTTP_REFERER']. If its value is not our website address, then the user will be redirected to our website homepage.

Of course, $_SERVER['HTTP_REFERER'] also has some limitations. For example, in some browsers, this value may be disabled or tampered with, resulting in inaccurate results. Therefore, when using $_SERVER['HTTP_REFERER'], we need to pay attention to these limitations and defects to avoid misjudgment or other security risks.

In short, $_SERVER['HTTP_REFERER'] is a very useful PHP variable, which can help us understand the source of access and implement some security controls. As long as we use it reasonably, we can bring more value and security to our website.

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