JavaScript function to get the referring URL of the current document.
/**
* Gets the referring URL of the current document.
*
* @return {String} The referring URL, or empty if not found.
*/
function getReferrer() {
var referrer = '';
try {
referrer = window.top.document.referrer;
}
catch (e) {
if (window.parent) {
try {
referrer = window.parent.document.referrer;
}
catch (e2) {
referrer = '';
}
}
}
if (referrer === '') {
referrer = document.referrer;
}
return referrer;
}