Javascript or PHP or Zend Framework - how to check previous url?

Question

Note: For marketting analyze, this url is in many other websites (ex: http://mysite.com/marketting ). So user clicks it and comes to my site.

Problem: But how can i check from where he came from? Did he came from facebook/ or google.com/ stackoverflow.com or wordpress.com or etc.com

How can you find, which link he clicked and reached to my site???

Tried:
i tried javascript: 
/* Doesnt provide previous url, if i am not in my localhost */
/* so, doesnt work */
var referer = document.referer;

/* PHP/ZF - doesnt work, cant get from where it came */
Zend_Debug::dump($_SERVER['REQUEST_URI'] . $_SERVER['HTTP_REFERER']);


$locale = new Zend_Locale();
// Return all default locales
$found = $locale->getDefault();
print_r($found);

// Return only browser locales
$found2 = $locale->getDefault(Zend_Locale::BROWSER,TRUE);
print_r($found2);

$found3 = $locale->getEnvironment(); // getBrowser()
print_r($found3);

Answer 1

Easily done with PHP:

$_SERVER['HTTP_REFERER']