Most "cheat" scripts function by manipulating the Document Object Model (DOM) or the SCORM (Sharable Content Object Reference Model) API. The SCORM API is the communication bridge between the course and the LMS. A script can intercept this communication and send a "success" or "completed" status to the LMS server immediately, tricking the server into thinking the user has finished the work.
Forcing the system to mark a module as "completed" without clicking through slides.