I just learned of this dispicable Comcast practice today and I am livid. Comcast began injecting 400+ lines of JavaScript code in to pages I requested on the internet so that when the browser renders the web page, the JavaScript generates a pop up trying to up-sell me a new modem. When you call the number in the popup, they’re quick to tell you that you need a new modem, which in my case is not true. I later verified with level-2 support that my modem is pefectly fine and I don’t need to upgrade. As deceptive as that is however, my major complaint is that Comcast is intercepting web pages and then altering them by filling them with hundreds of lines of code. Even worse is that I’ve had to speak to 7 different supervisors from all areas of Comcast and they have either never heard of the process, or those who were aware of the practice don’t know how to turn it off.
Source: Solved: Are you aware? Comcast is injecting 400+ lines of … – Xfinity Help and Support Forums