Zepto.js is a minimalist JavaScript framework for modern browsers, with a jQuery-compatible API
JavaScript Ruby
Pull request Compare This branch is 2 commits ahead, 702 commits behind madrobby:master.
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.


Zepto.js – a minimalist JavaScript framework

Zepto is a minimalist JavaScript framework for modern browsers with a largely jQuery-compatible API. If you use jQuery, you already know how to use Zepto.

See zeptojs.com for an extended introduction, downloads and documentation.

Zepto.js is licensed under the terms of the MIT License.


The official site offers a download of the default distribution of Zepto. This is good for starting out. However, at some point you might want to add some optional modules and remove some of the default ones you don't need, to keep the size at minimum. That's when you need to check out Zepto's source code and use the build commands.

You will need ruby, RubyGems, and rake installed on your system.

# dependencies:
$ ruby -v
$ gem -v
$ rake -V

# required to generate the minified version:
$ gem install uglifier

Build Zepto by running rake:

# build zepto.js
$ rake
Original version: 40.423k
Minified: 18.776k
Minified and gzipped: 7.033k, compression factor 5.747

The resulting files are:

  1. dist/zepto.js
  2. dist/zepto.min.js

To include optional modules and remove default ones, use the concat task. In this example, "touch" and "fx" are removed, but "data" is added:

$ rake concat[-touch:-fx:data] dist

Zepto modules

Zepto modules are individual files in the "src/" directory.

module default description
polyfill Provides String.prototype.trim and Array.prototype.reduce methods if they are missing (required for iOS 3.x)
zepto Core module; contains most methods
event Event handling via on() & off()
detect Provides $.os and $.browser information
fx The animate() method
fx_methods Animated show, hide, toggle, and fade*() methods.
ajax XMLHttpRequest and JSONP functionality
form Serialize & submit web forms
assets Experimental support for cleaning up iOS memory after removing image elements from the DOM.
data A full-blown data() method, capable of storing arbitrary objects in memory.
touch Fires tap– and swipe–related events on touch devices
gesture Fires pinch gesture events on touch devices
stack Provides andSelf & end() chaining methods


Get in touch:

  • IRC channel: #zepto on freenode.net
  • @zeptojs

Report a bug

  1. Check if the bug is already fixed in the master branch since the last release.
  2. Check existing issues. Open a new one, including exact browser & platform information. For better formatting of your report, see GitHub-flavored Markdown.

Running tests

Zepto test suite is in "test/*.html" files. Open the individual files in a web browser to run the tests. Files named with "_functional" are not automated tests, but require interaction. Automated tests are written using Evidence.js.

Detailed test output is logged in the JavaScript console of your browser.

Code style guidelines

  • function name() { } for named functions
  • function(){ } for anonymous functions
  • No curly braces for single-line control flow statements such as if & friends
  • Don't write semicolons that are optional
  • Put a single semicolon before statements that start with ( or [ (see above article as for why it's needed)
  • Use long, descriptive variable and method names
  • Use blank lines to separate "paragraphs" of code for readability
  • Use comments to describe non-obvious code behavior