Douglas Crockford's "Department of Style" Blog

Browser sniffing is a bad practice inspired by even worse practice. In browser sniffing, a program attempts to determine what sort of browser it is dealing with so that it can act accordingly. Sniffing can be done on the server, or by scripts in the browser.

When browser sniffing is done badly, it becomes a harsh barrier to innovation. Old applications will refuse to work correctly with new browsers because of assumptions that all future versions of a particular brand of browser will always require the same workarounds, or old applications will refuse to work with new browsers because the new browsers are unrecognized.

For example, Windows Update (http://www.update.microsoft.com/) refuses to work with IE8 because the updater was written before IE8 went into beta, and it practices a particularly brittle form of sniffing.

            Thank you for your interest in obtaining updates from our site.

            To use this site, you must be running Microsoft Internet Explorer 5 or later.

            To upgrade to the latest version of the browser, go to the Internet Explorer Downloads website.

Avoid browser sniffing. A better practice is to use a good Ajax library that will insulate your application, to the extent that it is possible, from the tragic history and current events of browser bugs and incompatibilities.

This blog appeared originally here. Copyright (c) 2008 Douglas Crockford.


AJAXWorld 2008 East in Next Week ! (18-20 March, 2008)

AJAXWorld 2008 East Keynotes

• Douglas Crockford, Architect at Yahoo! and Creator of the JSON data interchange format
  
  DOUGLAS CROCKFORD
  Can We Fix The Web?
  
  The Web needs fixing. The standards and recommendations that define it were last revised in 1999, since when it has grown from a document retrieval system into an application delivery system. The current Web is overly complex, visually underpowered, and hopelessly insecure. It is now under competitive assault by new proprietary platforms that hope to capture the next generation of applications. Can a system as large and as open as the Web heal and adapt itself to the challenges of the 21st Century.
  
  
• Anthony Franco, UX & UI Expert, President of Effective User Interface (EffectiveUI)
  
  ANTHONY FRANCO
  RIA Adoption in 2008 – Risks, Rewards, Challenges and Opportunities
  
  Last year, the overall demand for RIAs outpaced the qualified supply chain. Industry analysts expect the explosive growth to continue in 2008. This unprecedented increase in RIA adoption – especially by the Fortune 500 – will enable companies to hone their competitive edge and improve core business practices with fast, reliable, productivity-enhancing tools. RIAs can provide your customers with user experiences that leave your competition in the dust. While the flip side of the coin is that the world of RIAs can be fraught with costly risk, if you keep the risks and rewards front of mind, you can turn the 2008 RIA challenge into successful opportunities.
  
  
  Last Chance to Register for AJAXWorld 2008 East and Save $100 !
  
  

  AJAXWorld 2008 West Call for Papers Is Open! Submissions deadline: May 31, 2008 Next October's Conference is already receiving higher-caliber submissions from all over the Rich Internet Applications ecosphere. The theme of this October's AJAXWorld Conference & Expo 2008 West is 'Beyond AJAX to the RIA Era' and the Call for Papers, which is now open, specifically encourages submissions from exceptional speakers with high-quality use cases of the fast-emerging RIA alternatives. Submissions featuring such use cases as well as on dozens of other RIA topics have already begun streaming in to AJAXWorld Conference & Expo 2008 West, being held in San Jose, CA, on October 20-22, 2008. Click here to submit your speaking proposal today !