HTML DOM referrer Property

referrerProperty that returns the URL of the source document loaded into the current document.

Syntax:

document.referrer

　　　　var x = document.referrer;

The result of x will be:

All browsers fully support the Referrer property:

Property
referrer	Yes	Yes	Yes	Yes	Yes

Return Value:	A string, the property returns the URL of the source document loaded into the current document. If the user navigates directly to this page (not through a link, but for example through a bookmark), an empty string is returned.
DOM Version:	DOM 2Level