title: what is other option for HTTP_REFERER in php?
body: <p>I want to know is there any option/work sround for $_SERVER['HTTP_REFERER']. Because 'HTTP_REFERER' can not be trusted.
  Then What is other way to know that from which url the request has came from?.</p>
  
  <p>Here is the situation - 
  http:// abc.com/one.htmlwill have an iframe having src=http:// xyz.com/giv.php?param=1.
  How giv.php on xyz.com will know that request is coming from http:// abc.com/one.html?</p>