Future Media Standards & Guidelines

Browser Support Standards v3.72

1. Introduction

1.1. Scope of this Document

1.1.1. This standard applies to web browsers that are being used on desktop versions of Windows, Mac OS and Linux/Unix. This does not cover PDAs, mobiles, and other mobile devices.

1.2. Web Browser Support

1.2.1. The BBC accepts that the nature of the web medium is such that web pages cannot be produced in such a way as to be uniformly rendered in all browsers, so as to provide a consistent experience for all users. We accept that small variations in this experience are acceptable within the 'Levels of Support'. (See appendix 1 for details)

1.2.2. Web browsers are assigned a 'Level of Support' by the BBC Browser Support Standards Work Group. These levels of support are summarised in the Browser Support Table. (See appendix 2 for details of how these levels of support are decided).

1.2.3. There's nothing wrong with using all the latest bells and whistles to support funky features of newer browsers, but try to do it in a way that still allows users not supporting (or intentionally disabling) these features to access your basic content.

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2. 'Levels of Support' definitions

2.1. Support Level 1 - supported web browser - Support definition

2.1.1. All content MUST be readable and usable and all functionality MUST work.

2.1.2. Variations to presentation of content MUST be minimised.

2.1.3. Where CSS layout is used, the CSS MUST be rendered by supported web browsers, so that a fully-styled version of the page is presented to the user.

2.1.4. Variations between browsers are inevitable. In these situations, when deciding which browsers should offer a better experience than other browsers (i.e. which would be the closest to the original design), you MUST base your decision on which outcome would maximise the 'Objectives of Web Browser Support'.

2.1.5. Pages SHOULD be developed to maximise the user experience for users of the web browser with the highest proportion of users (IE7 PC at this time) UNLESS this would greatly compromise the 'Objectives of Web Browser Support'.

2.2. Support Level 2 - partially-supported web browser - Support definition:

2.2.1. All core content MUST be readable and usable and navigation MUST work.

2.2.2. Any degradation to (client-side) application functionality MUST be graceful degradation.

2.2.3. Any degradation to presentation MUST NOT obscure content.

2.2.4. Where CSS layout is used, you MAY choose to provide an unstyled version of the page to partially-supported browser.

2.3. Support Level 3 - unsupported web browser - Support definition:

2.3.1. No support or testing necessary.

2.3.2. Any web browsers not specifically listed in the support table MAY also be regarded as level 3; that is, unsupported.

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3. Support table

3.1. The table below defines the levels of support that MUST be adhered to. See also Appendix 2 'Objectives of Web Browser Support' and Appendix 3 'Decision Tree for Degradation of Browser Versions'.

Browser IE FF1 Chrome2 Opera1 Safari1 Konqueror
Platform Windows All Windows & Mac All All Linux
Level 1 6, 7, 8 FF 4.0.x, 3.6.x, 3.5.x, 3.0.x latest x.x 10.x, 9.6.x, 9.5.x 5.x, 4.x, 3.x  
Level 2 5.5 FF 2.0.x   9.x 2.x (Mac) 4.4x
Level 3 1, 2, 3, 4, 5 FF 1.5.x, 1.0.x   8- 1.x (Mac) 3-
Must test 6, 7, 8 FF 3.6.3
(PC Only)
latest x.x1 10.53 (PC) 5.0 (Mac, 4.0.3 (Mac)  
Should test 5.5 FF 3.0.6 (Mac), 3.5.7 (PC)   9.52, 9.64 3.2.1 (PC), 3.2.1 (Mac)  
Engine Trident (4-7), Ohare (1-3) Gecko Webkit Presto Webcore KHTML

Notes:

1 Supported versions are largely dictated by usage since the OS/Users are encouraged or prompted to upgrade.

2 Chrome Versions autoupdate without user intervention, so the supported version is the most recent non-beta version.

Browser Versions

Pre v1.0, Alpha, Beta and Release Candidate builds are not supported.

Browser Abbreviations

FF
Mozilla Firefox
IE
Microsoft Internet Explorer

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4. Appendix

4.1. Appendix 1 - Background

Web pages are available to viewers across the internet, anywhere in the world, using a wide variety of web browsers. These web browsers are developed by a number of different organisations with a variety of motives (some commercial), each of which interpret the source code used to produce web pages slightly differently. As a result, any single web page will not be uniformly rendered by all web browsers, to produce a consistent user experience as intended by the producer.

While this has improved over time, standardisation of web browsers is still to be achieved. The quest for standardising source code and the manner in which web browsers interpret it, has been led by the W3C (World Wide Web Consortium), an organisation whose stated role is to try to "lead the Web to its full potential". The support amongst the community of web developers for standardisation has come to be known as the 'Web Standards' movement.

This BBC standard exists so as to produce web pages that can be viewed (as consistently as can reasonably be achieved) by the greatest number of people possible.

HTML and CSS for separation of meaning from presentation

Because of the lack of web standards in the past, the only way to provide a consistent user experience was to use only the small range of source code features which worked across all web browsers. Specifically, the inconsistent rendering of CSS meant that CSS was not used much. HTML, which was more consistent, was used for both meaning and presentation; although its intended purpose was semantic rather than presentational.

With the advance of web standards, this has changed. HTML should thus be used to mark-up web content, to give it semantic meaning; while CSS should be used to define the presentation of content.

Not only is this how HTML and CSS are intended to be used (as outlined by the W3C), but it brings a wealth of advantages that considerably improve the potential to improve public value at the BBC; especially in terms of reducing costs and improving usability, e.g. accessibility. The use of HTML and CSS in this manner is often referred to as 'standards compliant code'.

Web browsers employ varying degrees of compliance to W3C recommendations (web standards) and consequently we often employ hacks and work-arounds* to meet the BBC's remit to provide content to the widest possible audience, while providing the optimum user experience. However, these hacks and work-arounds cost time and money, for supporting older, less standards-compliant browsers.

This BBC standard defines which web browsers are supported by the BBC, based on these and other contributory factors, to optimise value for users of the BBC website.

  • A hack is something that is not valid
  • a work-around is valid, but requires additional code
  • see BBC CSS Standards

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4.2. Appendix 2 - Objectives of Web Browser Support

When considering which 'Level of Support' a web browser should be assigned, the following are some of the issues that are considered.

  1. The BBC should provide value for money to the licence fee payer
    • Web standards are good for the web and meeting these standards offers public value for money.
    • Licence fee payers use a variety of web browsers. The BBC aims to provide the best possible experience to the largest number of people.
    • All license fee payers are considered to be valuable.
    • Some licence fee payers do not have the choice of using a popular, modern web browser.
    • Some people use accessibility tools - these people benefit greatly from web pages that are standards compliant.
  2. The BBC should not, where possible, provide a service that gives a competitive advantage to any particular product or service. (e.g. we should not add to any page 'works best in x browser').
  3. The BBC website represents the BBC globally. The BBC's image abroad is considered to be of importance and, therefore, the non-license fee-paying users of the BBC website are also considered important.

4.3. Appendix 3 - Decision Tree for Degradation of Browser Versions

4.3.1 See the figure linked to below for a visual explanation of the decision making process taken by the BBC Browser Support Standards Work Group when deciding upon the deprecation of browser versions. Decision tree diagram here.

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