Polyfills & why you might need them for web design

Pollyfills are scripts that allow you to use html5 and still not really break browsers that dont support the full feature set.

The repository can be found here on github https://github.com/Modernizr/Modernizr/wiki/HTML5-Cross-browser-Polyfills.

Please take a look at what you might be missing. Note many fraeworks already use some of these and you may already be taking advantage for example you are using bootstrap as a tempate js and css 'framework' to get the responsive webste design working.