HTML and CSS Reference
do just that: it detects the availability of various HTML5 and CSS3 features within a
user's browser and allows you to create fallbacks when a desired feature isn't currently
supported (see Figure 2-4 ).
Figure 2-4. The Modernizr site
where we create an audio player using HTML5's audio tag. If the user is viewing the
page with a browser that doesn't support the audio element, we want to display an error
message alerting the user of the problem.