JavaScript has been one of the core foundations of HTML5 since the beginning. Microsoft has been aggressively pushing HTML5 in Internet Explorer 10. So what happens when you take Microsoft’s desire to create proprietary programming languages and their insistence on HTML5? You get TypeScript, the company’s own version of JavaScript.

Microsoft announced that TypeScript is now available for developers and programmers to play around with. What’s the difference between TypeScript and JavaScript? Surprisingly, not a lot. Microsoft says that they created TypeScript as a way to help JavaScript scale to larger, more media rich HTML5 projects.

Some may be concerned that Microsoft is trying to replace JavaScript with TypeScript. That couldn’t be further from the truth. TypeScript is just an extension of JavaScript, and both languages can co-exist in your code. In fact, Microsoft claims that TypeScript is JavaScript and vice versa.

In essence, Microsoft is pushing TypeScript as a complement to traditional JavaScript development. It’s only meant to help developers create more media rich HTML5 applications. It only makes sense as Microsoft is aggressively pursuing HTML5 development in Internet Explorer 10 and Windows 8. The new language could help developers push the limits of HTML5.

Developers may be initially wary of another Microsoft-developed programming language, but Microsoft appears to have only the best intentions in mind with TypeScript. It’s completely open source and free to use. It compiles with JavaScript, and complements any preexisting code.

Interested developers can download an early preview of TypeScript here. You can also test it out for yourself in the TypeScript online playground. Finally, you can get the source code over at CodePlex.

For those who need a more visual explanation, Microsoft has also put together a video walkthrough of all the new features in TypeScript: