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It's a presentation framework based on the power of CSS3 transforms and transitions in modern browsers and inspired by the idea behind


impress.js may not help you if you have nothing interesting to say ;)


impress.js name in courtesy of @skuzniak.

It's an (un)fortunate coincidence that a Open/LibreOffice presentation tool is called Impress ;)


0.2 (browse, zip, tar)

  • tutorial/documentation added to index.html source file
  • being even more strict with strict mode
  • code clean-up
  • couple of small bug-fixes

0.1 (browse, zip, tar)

First release.

Contains basic functionality for step placement and transitions between them with simple fallback for non-supporting browsers.


Use the source, Luke ;)

If you have no idea what I mean by that, or you just clicked that link above and got very confused by all these strange characters that got displayed on your screen, it's a sign, that impress.js is not for you.


Fortunately there are some guys on GitHub that got quite excited with the idea of building editing tool for impress.js. Let's hope they will manage to do it.


Official demo

impress.js demo by @bartaz


CSS 3D transforms from meet.js summit by @bartaz

What the Heck is Responsive Web Design by John Polacek @johnpolacek presentation to Digibury by Stephen Fulljames @fulljames

Data center virtualization with Wakame-VDC by Andreas Kieckens @Metallion98

Asynchronous JavaScript by Mariusz Nowak @medikoo

Introduction to Responsive Design by Alec Rust [@alecrust] (

Websites and portfolios by @lioshi by Al Ingham @alingham by @NiceShots

museum140 Shorty Award promo video entirely made with ImpressJS by @thingsinjars

If you have used impress.js in your presentation (or website) and would like to have it listed here, please contact me via GitHub or send me a pull request to updated file.



Currently impress.js works fine in latest Chrome/Chromium browser, Safari 5.1 and Firefox 10 (to be released in January 2012). IE is currently not supported (IE10 is close, but not there yet - see below for details). It also doesn't work in Opera.

As it was not developed with mobile browsers in mind, it currently doesn't work on any mobile devices, including tablets.

Still interested?

Additionally for the animations to run smoothly it's required to have hardware acceleration support in your browser. This depends on the browser, your operating system and even kind of graphic hardware you have in your machine.

For browsers not supporting CSS3 3D transforms impress.js adds impress-not-supported class on #impress element, so fallback styles can be applied to make all the content accessible.

Even more explanation and technical stuff

Let's put this straight -- wide browser support was (and is) not on top of my priority list for impress.js. It's built on top of fresh technologies that just start to appear in the browsers and I'd like to rather look forward and develop for the future than being slowed down by the past.

But it's not "hard-coded" for any particular browser or engine. If any browser in future will support features required to run impress.js, it will just begin to work there without changes in the code.

From technical point of view all the positioning of presentation elements in 3D requires CSS 3D transforms support. Transitions between presentation steps are based on CSS transitions. So these two features are required by impress.js to display presentation correctly.

Unfortunately the support for CSS 3D transforms and transitions is not enough for animations to run smoothly. If the browser doesn't support hardware acceleration or the graphic card is not good enough the transitions will be laggy.

Additionally the code of impress.js relies on APIs proposed in HTML5 specification, including classList and dataset APIs. If they are not available in the browser, impress.js will not work.

Fortunately, as these are JavaScript APIs there are polyfill libraries that patch older browsers with these APIs.

For example IE10 is said to support CSS 3D transforms and transitions, but it doesn't have classList not dataset APIs implemented at the moment. So including polyfill libraries should help IE10 with running impress.js.

And few more details about mobile support

Mobile browsers are currently not supported. Even iOS and Android browsers that support CSS 3D transforms are forced into fallback view at this point.

Anyway, I'm really curious to see how modern mobile devices such as iPhone or iPad can handle such animations, so future mobile support is considered.

iOS supports classList and dataset APIs starting with version 5, so iOS 4.X and older is not likely to be supported (without polyfill code).


Copyright 2011-2012 Bartek Szopka. Released under MIT License.