Skip to content


Subversion checkout URL

You can clone with
Download ZIP
A framework for building exercises to work with Khan Academy.
HTML JavaScript CSS Python Shell Makefile

Prevent cheating with offline hints.

This solves the problem posed by the [Prevent using offline hints to cheat project](
Previously, a user could disconnect from the internet, take a hint, then
reconnect without any penalty.

Now if they try this, their browser will remember that they took a hint
when they reconnect and click the "take a hint" button for them.

Test Plan:
Follow the test plan below for the following environments: Chrome,
Chrome Incognito, Firefox, Firefox Private, Safari, Safari Private.

1) Open an exercise on your learning dashboard that has hints.
2) Kill your dev server
3) Take a hint
4) Refresh the page to show a blank page
5) Start your dev server
6) Refresh the page to show the exercise again
7) Verify that it shows that you still took a hint (unless you're in
   Safari Private, in which case it should just not error).

Reviewers: alex, emily

Reviewed By: emily

Differential Revision:
latest commit 4a37397c96
@brownhead brownhead authored
Failed to load latest commit information.
build Fix lint in build/pack.js again.
css Ensures that the "Show scratchpad" button works
exercises Increase the range of questions
fonts Move all answer area content to the bottom of the question area
genfiles Remove references to `USERNAME`
images Update badge images and fix clipping
local-only Upgrade katex in to v0.2.0
test Tests: Make tests run again
third_party Add new exercise colors to KAthJax and Math.js
tools Add tools/, which will be automatically run by khan-linter.
utils Increase the range of questions
.arcconfig Fix the Show Answers button when reporting an exercise issue.
.arclint add default .arclint file
.gitignore Fixed a few TODOs.
.gitmodules Move qunit to a more-global directory
.travis.yml Try a different room ID!
Makefile Get rid of an obsolete comment. Link to careers page, not Jobvite
exercises-stub.js (khan-exercises) Replace top-level var declaration with explicit glob…
history.js Fix coach report answer correctness color
interface.js Prevent cheating with offline hints.
khan-exercise.js Fix the Show Answers button when reporting an exercise issue.
lint_blacklist.txt Use webpack to bundle JS together, not requirejs
main.js Use requirejs for module loading
package.json Rewrite pack.rb in javascript, to remove the main ruby dep on our cod…
requirements.txt First pass at creating a new script for our i18n e…

Khan Academy Exercises

Copyright (c) 2014 Khan Academy

The exercise framework is MIT licensed.

The exercises are under a Creative Commons by-nc-sa license.

Exercise Framework

Khan Academy has created a generic framework for building exercises. This framework, together with the exercises themselves, can be used completely independently of the Khan Academy application.

The framework exists in two components:

  • An HTML markup for specifying exercises.
  • A jQuery plugin for generating a usable, interactive, exercise from the HTML markup.

Using the Framework Locally

You need to serve the files from some sort of a server. You can't just open the files directly in a browser. For example:

cd khan-exercises
python -m SimpleHTTPServer # or python3 -m http.server

Now if you open your browser to http://localhost:8000 (or you should see the contents of the khan-exercises directory. Navigate to the exercises subfolder, and an HTML file under there to see an exercise.

Exercise Development

This framework supports over 450 of our current math exercises including updated versions of many exercises Sal built for his cousins before he made his first video! New exercises on Khan Academy, however, are now written by many content experts using Perseus and stored in our datastore as individual questions.


If you're passionate about providing a free world-class education for anyone, anywhere and want to apply to be a full-time or intern software developer at Khan Academy, please do so.

Something went wrong with that request. Please try again.