Anthony Milner

Have you ever eaten trifle? A trifle is a dessert starting with a layer of cream then a layer of fruit and jelly and then finally a layer of sponge cake soaked in port…yum! I love analogies and today I am using a trifle analogy to explain progressive enhancement (PE) in web development and design.

Jeremy Keith gave a really good presentation on this concept at the recent Web Directions conference in Sydney. PE is a very simple and effective strategy to follow to ensure that we build accessible and search engine friendly websites.

The foundation of any website is its content, if a user can’t read the content then we have a problem. If there is a really cool widget on my site which earlier browsers or secure organisations do not support the user could get partial content or even worse the page fails to load.

Progressive enhancement is a layered approach which ensures that your site first and foremost presents accessible content (cream), adding an external stylesheet gives it a beautiful look and feel (fruit and jelly) and finally enhanced behavior is provided by adding unobtrusive externally linked JavaScript (sponge cake soaked in port – when I was young my Mum would not let me partake in this layer in the same way that a bank may disable JavaScript on the desktop).

This approach ensures that everyone can view the content no matter what their configuration with the added bonus that search engines only consume the cream.