LD SoftwareBespoke Software, Web Design, Security Consultants and Host Services.


You have been warned!
We have caught 5848 shameful hackers.


Paypal Referral
Sign up for PayPal and start accepting credit card payments instantly.

Link Exchange
Join our free link exchange

Click Here
Progressive enhancement

Web Design & Development Guide

Progressive enhancement

Home | Up

Progressive enhancement is a label for a particular strategy of Web design that emphasizes accessibility, semantic markup, and external stylesheet and scripting technologies, in a layered fashion that allows everyone to access the basic content and functionality of a Web page, using any browser or Internet connection, while also enabling those with better bandwidth or more advanced browser software to experience an enhanced version of the page.


"Progressive Enhancement" was coined by Steven Champeon, of Web design firm hesketh.com, in a series of articles and presentations for Webmonkey and the Sxsw Interactive conference between March and June of 2003.[1][2]

Introduction and background

The strategy is an attempt to subvert the traditional Web design strategy known as "graceful degradation", wherein designers would attempt to create Web pages for the latest browsers that would also work well in older versions of browser software. Graceful degradation was supposed to allow the page to "degrade", or remain presentable even if certain technologies assumed by the design were not present, without being jarring to the user of such older software (hence "gracefully"). In practice, graceful degradation has been supplanted by an attitude that the end user should "just upgrade". This attitude is due to time and budget constraints, limited access to testing alternate browser software, as well as the widespread belief that "browsers are free". Unfortunately, upgrading is often not possible due to IT department policies, older hardware, and other reasons. The "just upgrade" attitude also ignores deliberate end user choices and the existence of a variety of browser platforms; many of which run on handhelds or in other contexts where available bandwidth is paltry, or where support for sound or color, limited screen size, and so forth are far different from the typical graphical desktop browser.

In Progressive Enhancement (PE) the strategy is deliberately reversed: a basic markup document is created, geared towards the lowest common denominator of browser software functionality, and then the designer adds in functionality or enhancements to the presentation and behavior of the page, using modern technologies such as Cascading Style Sheets or JavaScript (or other advanced technologies, such as Flash or Java applets or SVG, etc.) All such enhancements are to be externally linked, in order to avoid forcing browsers of lesser capability to "eat" data they do not understand and cannot handle, or which would swamp their Internet connection.

The PE approach is derived from Champeon's early experience (c. 1993-4) with SGML, before working with HTML or any Web presentation languages, as well as from later experiences working with CSS to work around browser bugs. In those early SGML contexts, semantic markup was of key importance, whereas presentation was nearly always considered separately, rather than being embedded in the markup itself. This concept is variously referred to in markup circles as the rule of separation of presentation and content, separation of content and style, or of separation of semantics and presentation. As the Web evolved in the mid-nineties, but before CSS was introduced and widely supported, this cardinal rule of SGML was repeatedly violated by HTML's extenders. As a result, web designers were forced to adopt new, disruptive technologies and tags in order to remain relevant. With a nod to graceful degradation, in recognition that not everyone had the latest browser, many began to simply adopt design practices and technologies only supported in the most recent and perhaps the single previous major browser releases. For several years, much of the Web simply did not work in anything but the most recent, most popular browsers. This remained true until the rise and widespread adoption of and support for CSS, as well as many populist, grassroots educational efforts (from Eric Costello, Owen Briggs, Dave Shea, and others) showing Web designers how to use CSS for layout purposes.

PE is based on a recognition that the core assumption behind "graceful degradation" — that browsers always got faster and more powerful — was proving itself false with the rise of handheld and PDA devices with low-functionality browsers and serious bandwidth constraints. In addition, the rapid evolution of HTML and related technologies in the early days of the Web has slowed, and very old browsers have become obsolete, freeing designers to use powerful technologies such as CSS to manage all presentation tasks and JavaScript to enhance complex client-side behavior.

First proposed as a somewhat less unwieldy catchall phrase to describe the delicate art of "separating document structure and contents from semantics, presentation, and behavior", and based on the then-common use of CSS hacks to work around rendering bugs in specific browsers, the PE strategy has taken on a life of its own as new designers have embraced the idea and extended and revised the approach.

Core principles

Progressive Enhancement consists of the following core principles:

  • all basic content should be accessible to all browsers
  • all basic functionality should be accessible to all browsers
  • sparse, semantic markup contains all content
  • enhanced layout is provided by externally linked CSS
  • enhanced behavior is provided by unobtrusive, externally linked JavaScript
  • end user browser preferences are respected

Support and adoption

Jim Wilkinson created a page for Progressive Enhancement Wiki to collect some tricks and tips and to explain the overall strategy.[3] Designers such as Jeremy Keith have shown how the approach can be used harmoniously with still other approaches to modern Web design (such as Ajax) to provide flexible, but powerful, user experiences.[4] Others, including Dave Shea, have helped to spread the adoption of the term to refer to CSS-based design strategies. Organizations such as the Web Standards Project have embraced PE as a basis for their educational efforts. In 2006 Nate Koechley at Yahoo! mades extensive reference to PE in his own approach to Web design and browser support, Graded Browser Support (GBS).[5] Steve Chipman at AOL has referred to PE as a basis for his Web design strategy.[6] David Artz, friend of Steve and leader of the mighty AOL Optimization team, developed a suite of Accessible Rendering Technologies - experiences based on these principles - and invented a technique for disassembly of the "enhancement" on the fly, saving the user's preference. Chris Heilmann discusses the importance of targeted delivery of CSS so that each browser only gets the content (and enhancements) it can handle.[7] Many Web design agencies have begun to advertise that they provide progressive enhancement as a core service.

Benefits for accessibility

Web pages created according to the principles of PE are by their nature more accessible, because the strategy demands that basic content always be available, not obstructed by commonly unsupported or easily disabled scripting. Additionally, the sparse markup principle makes it easier for tools that read content aloud to find that content. It is unclear as to how well PE sites work with older tools designed to deal with table layouts, "tag soup," and the like.

Benefits for search engine optimization (SEO)

Improved results with respect to Search Engine Optimization is another side effect of a PE-based Web design strategy. Because the basic content is always accessible, and the markup is clean and easily parsed for structure and intent, it becomes much easier to tune the content to improve SEO results.

Criticism and responses

Some skeptics, such as Garret Dimon, have expressed their concern that PE is not workable in situations that rely heavily on JavaScript to achieve certain user interface presentations or behaviors.[8] Jeremy Keith is to present Hijax: Progressive Enhancement with Ajax at XTech06, suggesting that the two are compatible. Others have countered with the point that informational pages should be coded using PE in order to be indexed by spiders, and that even Flash-heavy pages should be coded using PE. In a related area, many have expressed their doubts concerning the principle of the separation of content and presentation in absolute terms, pushing instead for a realistic recognition that the two are (and some would say should be) inextricably linked.

See also


Footnoted references
  1. ^ Champeon, Steven (2003), Progressive Enhancement and the Future of Web Design, Webmonkey
  2. ^ Champeon, Steven & Finck, Nick (2003) Inclusive Web Design for the Future, SxSWi presentation
  3. ^ Wilkinson, Jim (2003), CSS-Discuss Wiki page on Progressive Enhancement
  4. ^ Adactio, Progressive Enhancement with AJAX
  5. ^ Nate Koechley, Graded Browser Support
  6. ^ Steven G. Chipman, New Skool DOM Scripting
  7. ^ Chris Heilmann, Double Vision – Give the Browsers CSS They Can Digest
  8. ^ Dimon, Garret, The Reality of Progressive Enhancement

Related Reading



Home | Up | Cascading Style Sheets | Printer friendly | Brochureware | Digital strategy | DOM scripting | Fahrner Image Replacement | Microformat | Progressive enhancement | Rollover | Spacer GIF | Techniques for creating a User Centered Design | URL redirection | Web Interoperability | Web modeling | Web template | Web-safe fonts | Website architecture | Website wireframe

Web Design & Development Guide, made by MultiMedia | Websites for sale

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.


Text Ads
There isn't content right now for this block.

Community Login


People Online:
Visitors: 32
Members: 1
Total: 33

Online Now:
01 : Monty

Like my code
Then please make a donation.

Which help me produce more free code.

Paypal Verified


Powered by PHP-Nuke

Valid CSS!

Valid Robots.txt

Bad Behavior

[Valid RSS]

[Valid RSS]
You can syndicate our News with backend.php And our Forums with rss.php
You can also access our feeds via Feedburner Site News and LD Software Forums
© 2009 ld-software.co.uk All Rights Reserved.
PHP-Nuke Copyright © 2005 by Francisco Burzi. This is free software, and you may redistribute it under the GPL. PHP-Nuke comes with absolutely no warranty, for details, see the license.
Page Generation: 0.40 Seconds