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Browsers support

Mandatory requirementEUROPA  web sites must work on as many platforms and devices as possible, but at least on the browsers listed in the table below.


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Web pages can be accessed by a wide variety of web browsers on different platforms. Every browser interprets the source code used to produce web pages slightly differently. This means that a web page will not be uniformly rendered by all web browsers as it would have been expected. 

To ensure that web sites work on as many platforms and devices as possible you should:

  • use standards: If you develop standards-compliant code (e.g. HTML, CSS, JavaScript, DOM, Mobile Web) you can be confident that your website will work on a wide variety of platforms and devices.
  • test with browsers: If you then test with a few popular browsers you can be confident that the website works for as many users as possible.

Which browsers should be tested

Public sector web sites have a responsibility to be inclusive and not to exclude groups of users, therefore does EUROPA aim to provide the best possible experience to the largest number of users. This means that browser testing should be as inclusive as possible. However, this needs to be balanced against increased testing times and costs because the list of browsers, versions and platforms could be endless.

As a public service, it should not give a competitive advantage to any particular enterprise or service. The fact that some Internet users may do not have the choice of using the latest most popular browsers or that some people use accessibility tools to browse the web should also be taken into consideration.

The IPG team started to collect browser statistics from EUROPA websites going back as far as March 2013. Only browsers with a market share higher than 2% are considered in order to allow for a more simplified and more focussed analysis.

As a general rule, all EUROPA pages should be tested - and any issues resolved - with the browsers and platforms used by 2% or more of EUROPA users. The 2% is a useful threshold to keep the balance between usability and efficiency. 

Browsers and operating systems used by less than 2% of EUROPA users are not required to be tested. This does not imply that those browsers or systems should not be supported. Less popular browsers that support standards are assumed to work. However, assistive technology (screen readers or any other alternative web browsing systems) and open source operating systems (e.g. Linux, FreeBSD) should be tested even if they account for less than 2%. 

There are several websites that provide global statistics for browser usage, however these figures may not be representative for the users of EUROPA. Links to information on the most popular browsers accessing the European Commission or interinstitutional websites are available from the "Tool" page of the "EUROPA Analytics" section.  In a nutshell it can be concluded that the market share of all browsers with more than 2% of users accessing EUROPA is around 70% to 75%. This means that a quarter of all users do not use a main stream browser.

According to our statistics the main browsers in use have the following share:


Market Share

Google Chrome (latest version)

20% - 25%

Mozilla Firefox (latest version)

9% - 14%

Internet Explorer (versions 7, 8, 9, 10)

15% - 28%

   - IE 10

2% - 5%

   - IE 9

4% - 9%

   - IE 8

5% - 11%

   - IE 7

2% - 3%

- Safari (latest version)

2% - 5%

- Mobile Safari (latest version)

2% - 5%

This table allows for the following conclusions:

  1. Because Google Chrome and Mozilla Firefox are updated once a month and due to the automatic update feature of those 2 browsers, is it very likely that users do use the latest versions. This makes it too resourceful to update the browser compatibility list every month. Yet, in order to give some guidance, we do recommend that browsers that don't have a market share of more than 2% for 3 consecutive months don't have to be tested specifically.
  2. Internet Explorer is represented in various versions in this table as it is updated less frequently than Google Chrome or Mozilla Firefox. Each of these versions has a different level of HTML 5 support, which makes testing difficult.
  3. Mobile Safari is the only mobile browser with a market share of more than 2%. The fragmentation of browsers running on Android doesn't allow for one particular browser to stand out.

Browsers compatibility list

The browser compatibility list accommodates the use of HTML4 and HTML5. Although HTML4 is still the recommended version by the IPG team, we are aware that more and more sites are using HTML5. Please be aware that HTML5 is not a final version yet.

Whereas all browsers – including Internet Explorer 7 and 8 – fully support HTML4 since a number of years, support for HTML5 varies very much among browsers. In Internet Explorer 7 and 8, support for HTML5 is very poor, whereas the latest version of Google Chrome, Mozilla Firefox and Apple Safari cover coherently most of the features offered by HTML5.

Testing only for HTML doesn't mean that your page qualifies for browser compatibility. It should be taken into consideration that – as outlined in How and what should be tested – other criteria such as compliance with CSS or with potentially used JavaScript libraries or frameworks are equally important for the successful rendering of your website.

Here the browser compatibility list (Last update: 14/03/2018. Next planned revision: November 2018):







Firefox 56+


Chrome 60+

Safari 11+

These browsers have to be supported in such a way that all content must be readable and all functionalities must work. Presentation of content must not vary substantially.

It has to be ensured that that core content and core features have to be available for all users, regardless of the browser they use. This approach, known as progressive enhancement, means features that rely on the latest browser technologies will fall away for browsers that don’t support them without adversely affecting the user experience.

To test how your website works on different browsers and devices, you may use our dedicated Browsers test environment Restricted area: This link points to internal pages and may not work if you are browsing as an external user..

People with disabilities, whether temporary or permanent (such as hearing, visual, physical or cognitive impairment) use a wide range of alternative approaches, different from traditional mouse-and-screen-based browsers. To understand and test less known approaches used for browsing read the section on accessibility evaluation tools and assistive technology.

The mobile web is rapidly growing and therefore web sites might also be tested with mobile devices. However, there are such a large number of varying devices that may render this impractical. Code to standards and develop a dedicated web site for those sections that could be of interest for web mobile users, could be a valuable alternative. W3C has published a recommendation for Mobile Web Best Practices which helps designers ensure that all web content is compatible with mobile devices without adaptation.   

To get an idea of how your website works on different mobile devices, you may wish to use mobile devices emulators.


How and what should be tested

You should check that the content, functionalities and display work as foreseen. However, there may be minor differences in the way that the web site is displayed. The aim is that users do not notice anything appears wrong.  

When testing web site functionality, you may test the navigation, forms behaviour, JavaScripts, browser back button, cookies, embed content, keyboard browsing, etc.

Some content can be unavailable to users who navigate the site with some browser options being disabled. Therefore, you should also test your website to make sure that it works with scripting, plug-ins, images and CSS turned off.

Keyboard browsing must be tested and be fully operational. Display with the accessibility features offered in different platforms such as high contrast or text/links colour changes should also be tested.


Cross-browser compatibility tools

Use our Browsers test environmentRestricted area: This link points to internal pages and may not work if you are browsing as an external user. to check compatibility with different browsers and platforms.