Javascript input() and output() functions

Hi, I've been looking at the solutions for some of the Javascript problems, and a lot of users are using input() and output() functions to put in the data and output the results. However, as far as I know, these functions aren't available in standard Javascript. Are they available through some sort of particular engine/interpreter? Or are they just placeholders that some people are using? Thanks for any clarification.

Oh okay, thanks a lot!