Document.referrer Value When Clicked From Email Box

document.referrer Returns the URI of the page that linked to this page. The value is an empty string if the user navigated to the page directly (not through a link, but, for examp

Solution 1:

It's easy enough to fake the document.referrer value to spoof another site, but you can't supply it with a value when coming from an email link, since it's not being loaded by another web page in the browser.

EDIT: It would be possible to simulate a document.referrer value when an email link is clicked -- you would send the user to another web page, which would supply the referrer value, then pass them along to the destination page -- but for your purposes, that's not a likely situation.

Short answer: If it has a value set, unless someone is trying to spoof it, it didn't come from an email link.