Debugging greasemonkey scripts directly is very hard as the script is loaded in a not-so-familiar environment and the errors are reported in line numbers are interpreted by greasemonkey. GM Simulator solves this problem by wrapping most of greasemonkey's function so that the script can be loaded like any other script while development. Additionally, the use of the script can also be demonstrated without having to install the script. Since this is a simulated greasemonkey environment, not all of greasemonkey's scripts will work.