A design and development technique which delivers essential features regardless of browser capability and advanced features where supported
Progressive enhancement is an approach to web design that encourages the use of web technology layers (e.g. HTML, CSS, Javascript, images etc.) in a manner that enables everyone to access the basic content and functionality of a website, regardless of their browser capability or connectivity. This base experience can then be enhanced for those with a browser or connection capable of displaying them. Progressive enhancement can be best explained by a quote from American Stand-Up comedian Mitch Hedberg: ‘An escalator can never break – it can only become stairs’.
For example, CSS3 animations enhance the user experience for browsers that support them, while older browsers still get the basic functionality.
The difference between progressive enhancement and graceful degradation is debated. The former focuses upon delivering a base experience which can than be enhanced where possible, whereas the latter focuses upon allowing the website to remain presentable even if technologies assumed by the design (such as Javascript) are not present.