TypeScript - typed JavaScript working in browser like ES5/ES3

Taken from here: http://weblogs.asp.net/dwahlin/getting-started-with-es6-%E2%80%93-the-next-version-of-javascript

TypeScript is a superset of JavaScript that lets you write “typed” ES6 code (define numbers, strings, booleans, etc.) while still allowing it to work in any browser out there by “compiling” it to ES5/ES3. I’ll be showing TypeScript code as well in this series when it applies to a specific ES6 feature.