The JavaScript program below prompts for a lesson file, and, when one is provided, quizzes the user with the questions from it. When the user answers all questions correctly the specified times in a row, the lesson is counted as complete.

The lesson file should be a text file. Question and answer pairs are delimited by blank lines. The final line before the blank line is the answer; all the preceding lines are part of the question. Any lines that start with "<" are interpreted as HTML.

A sample lesson is provided. More lessons are linked from this page.