Alternative for $_SERVER['HTTP_REFERER'] PHP variable in MSIE

If you only need to use the referrer information internally for your website (ie: between pages of your website, not externally), you can manually keep track of a user's referrer information.

// Get the full URL of the current pagefunction current_page_url(){    $page_url   = 'http';    if(isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == 'on'){        $page_url .= 's';    }    return $page_url.'://'.$_SERVER['SERVER_NAME'].$_SERVER['REQUEST_URI'];}/* (Assuming session already started) */if(isset($_SESSION['referrer'])){    // Get existing referrer    $referrer   = $_SESSION['referrer'];} elseif(isset($_SERVER['HTTP_REFERER'])){    // Use given referrer    $referrer   = $_SERVER['HTTP_REFERER'];} else {    // No referrer}// Save current page as next page's referrer$_SESSION['referrer']   = current_page_url();

Then, to access the referrer, just use the $referrer variable.

if(isset($referrer)){    echo 'Referred from "'.$referrer.'"';    echo '<a href="'.$referrer.'">Back</a>';} else {    echo 'No referrer';}

That way, if a user visits http://www.example.com/page_1.php, they will see the referrer information if their browser has provided it, otherwise no referrer. Then when they visit http://www.example.com/page_2.php, and any subsequent pages of your site, the referrer will be accessible.

Please don't use session to guess the referrer. This will lead to undesired behaviour and strange errors.

If you really need to know the referring page, pass it via request parameter. You can add the parameter with JS script or on the server side.

jQuery variant for all links on the page:

$(document).ready(function(){    $('a').on('click', function(e) {        url = this.getAttribute('href');        // Check if the page is internal.        if (url.charAt(0) != '/') {            return;        }        e.preventDefault();        // Append referrer.        url += url.indexOf('?') === -1 ? '?' : '&';        url += 'referer=' + encodeURIComponent(document.URL);        window.location = url;    });});