What is graceful degradation

It also ensures that screen readers can understand the application, which is relevant to the accessibility of a website.

In addition, it is easier to test the functionality of websites based on progressive enhancement rather than graceful degradation. The implementation of graceful degradation for a web application begins with determining which outdated browsers and devices should still be supported. The goal is not to provide the best possible experience for users of older browsers, but to develop the best possible solution for most advanced browsers.

This means that the functionality of a web page in older browser versions is less important than the display of its content. For example, if a website is accessed from an old Blackberry or laptop with Internet Explorer 6, the page structure has to ensure that the page can still be displayed on those older browser versions.

Thereby functionality takes a back seat. Therefore, the functionality of a page is always designed for the latest browser versions. After that, older browser versions are used to test which functions and CSS elements can be removed with as little loss of usability as possible. You should also make sure that the page can be used with purely text-based browsers.

The principle of graceful degradation can also be used for mobile optimization. All of this makes for a very fragile development environment, for example offices where the default is a 9-year old browser with scripting and plugins disabled because of security reasons , low resolutions and computers that are barely managing the load of running office software are pretty common.

But this attitude can cause us to forget that these people might be very important to the success of our products. We work in the unknown and we need to find a way to make it work. This is where both graceful degradation and progressive enhancement come into play.

So, graceful degradation is the practice of building your web functionality so that it provides a certain level of user experience in more modern browsers, but it will also degrade gracefully to a lower level of user in experience in older browsers.

This lower level is not as nice to use for your site visitors, but it does still provide them with the basic functionality that they came to your site to use; things do not break for them. Progressive enhancement is similar, but it does things the other way round. You start by establishing a basic level of user experience that all browsers will be able to provide when rendering your web site, but you also build in more advanced functionality that will automatically be available to browsers that can use it.

In other words, graceful degradation starts from the status quo of complexity and tries to fix for the lesser experience whereas progressive enhancement starts from a very basic, working example and allows for constant extension for future environments. Degrading gracefully means looking back whereas enhancing progressively means looking forward whilst keeping your feet on firm ground. Arguably links that allow users to print the current document are useless — hitting the printer icon in their browser does the same thing.

User testing however shows that as a last step in a booking process eg on an airline web site they are a good re-affirming call to action. Users feel in control and get the sense of finishing what they started.

In JavaScript it is easy — the window object of the browser has a print method that can be called to start a printout. A system that continues to run at some reduced level of performance after one of its components fails. It is a level below fault-tolerant systems, which continue running at the same rate of speed.

For example, a two-computer complex employing graceful degradation would be reduced to using one system if the other fails. With fault tolerance, a third computer would be standing by to take over in the event of failure. If you see a notable percentage of people using a certain older browser, then you will likely want to support that browser or risk losing that business.

If you look at your analytics and see that no one is using an older browser version, you are probably safe in making the decision not to worry about fully supporting that outdated browser and testing for it. So the real answer to the question of how far back your site needs to support is: "however far back your analytics tell you your customers are using.

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