Hi Olivier: The length of the log can be extended to yesterday's data by changing the var ms variable in background.js. var ms gives the length of the log in characters. I figured than a hundred thousand characters would be enough when I developed nifty kl. How many characters do you think you need? Mind you nifty kl will get slower as the log size increases. Cheers, Daniela

Update 24 February 2018: The latest version 1.5.3 of nifty keylogger should also display data stored yesterday.