javascript - How to get the url of previous page in chrome extension

Question

I am trying to build a chrome extension for which I need to parse webpage from which files get downloaded. The problem is that when I click the download link I am redirected to another page from where my file gets downloaded.Now by using downloadItem.url; I am able to get the url but the url is of the page which I am redirected to ,But what I want is the url of page which contains the downloading link .Is there any way that I could get the url of previous page or I have to parse each and every webpage to check for the download link?for eg this

Answer 1

Waitting for answers