This is a simple script that allows you to measure the input lag of your TV.
You just run this script on a computer connected to the tv, take a picture that includes both screens and you can see how much input lag your tv has (compared to your computer).
you can run the script directly here: http://htmlpreview.github.io/?https://github.com/mezga0153/input-lag-tester/blob/master/test.html