What is modernizr?

Answer 1

Modernizr is an open source, MIT-licensed JavaScript library that detects support for many HTML5 & CSS3 new features. You should always use the latest version. It runs automatically

<script src="modernizr.min.js"></script>
if (Modernizr.canvas) {
// let's draw some wonderful shapes!
} else {
// no browser support for canvas available 
}