function getReferrer() {  
  var url = document.referrer;  
  if (! url) return "";  

  if (url.indexOf("/index.html") != -1) {  
    url = url.substring(0, url.length - 10);  
  }  

  return url;  
}  

// Returns the host that served this request  
function getHost() {  
  var parts = window.location.href.split("/");  
  return parts[0] + "//" + parts[2] + "/";  
}  

function checkReferrer() {  
  return (getReferrer() == getHost());  
}  

var isFromHomePage = checkReferrer();