Progressive enhancement versus graceful degradation

You're probably aware of the phrases "progressive enhancement" and "graceful degradation". These two concepts are methodologies for dealing with wide and varied browser support and spark fierce debate within the web community. Whilst initially they may seem inter-changeable terms, they are actually fundamentally opposed. Here's my take…

Graceful degradation means creating a site for modern browsers and then ensuring that certain older browsers are afforded a usable experience. Features degrade in older browsers and there is usually a cut-off point in which the oldest browsers aren't supported. There are also occasions where users are merely warned that there is a problem with their browser and workarounds are suggested (for example, "your browser is a joke—get a new one!")

Progressive enhancement is the reversal of graceful degradation. Progressive enhancement begins with markup that adheres to web standards, meaning it will be usable by...