Polyfills, a term coined by Remy Sharp back in 2010, are scripts that mimic a future API providing fallback functionality to older browsers. The rise of HTML5, CSS3 and ES5 resulted in various polyfills being written by developers all over the world to fill in the gaps of browser support, so we can use new standards before they are universally adopted by browser makers. In this talk, we will explore various techniques commonly employed in good polyfills and shims, so you can start writing your own when a polyfill for the feature you need is not already available. This way, not only you will be able to improve your own workflow, but also share it with the world and give back to the community. Less