document.referrer in JS

[hpl]

I want to use the object document.referrer because I need some information on the URL I have visited before the actual site. I have used this function where I want to write my previous site to a text field, but nothing happens. What could be wrong?

function tester() {
	if (document.referrer == "http://intranet") {	
		sprog = "Not OK";
		document.calc_heat.test.value=sprog;
		} 
	else {
		sprog = document.referrer ;
		document.calc_heat.test.value=sprog;
		} 
	
}