How to implement button return to previous page in php

In a web page, sometimes it is necessary to implement a button so that users can return to the previous page after clicking it. For example, in a form page, after the user fills in the information, if he wants to go back to the previous page and review the information again, he needs a button to return to the previous page. How to implement this function in PHP?

Let’s first learn how to get the address of the previous page in PHP. In PHP, you can use $_SERVER['HTTP_REFERER'] to get the address of the previous page, but this value does not necessarily exist. Some browsers will disable this function, or when entering the current page from other ways, this value will also exist. Uncertainty. Therefore, we need to do some compatibility processing in the code.

The code is as follows:

<?php
if(isset($_SERVER[&#39;HTTP_REFERER&#39;])){
    $last_page = $_SERVER[&#39;HTTP_REFERER&#39;];
} else {
    $last_page = &#39;javascript:history.back()&#39;;
}
?>

In this code, we first determine whether $_SERVER['HTTP_REFERER'] exists. If it exists, assign it to the variable $last_page; if it does not exist , then assign the variable $last_page to "javascript:history.back()". The history.back() method in JavaScript is used here, which can realize the function of returning to the previous page.

Next, we can add a button to return to the previous page. The code is as follows:

<button onclick="window.location.href=&#39;<?php echo $last_page; ?>'">返回上一页</button>

In this code, we use the onclick event to bind the click event of the button. When the button is clicked, the window.location.href method in JavaScript will be called to set the address to the address represented by the variable $last_page, thereby realizing the function of returning to the previous page.

The above is how to implement the return to previous page button in PHP. Through this method, when needing to return to the previous page, the user can directly click the button instead of manually operating through the browser's return button, which improves interactivity and user experience.

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