How to get referrer URL in PHP

How to get referrer URL in PHP

Referrer show you where to user come on our site. In other words we can say last url of browser is Referrer URL.

<?php
$ref = getenv("HTTP_REFERER");
echo $ref;
?>
<?php
    if($_SESSION['refurl']==null)
    {
        $ref = getenv("HTTP_REFERER");
        $_SESSION['refurl']=$ref;
        echo $ref;
    }
    else
    {
   echo $_SESSION['refurl'];
    }
?>