Javascript is the ubiquitous new language of the web. Used both for frontend and backend MVC, javascript is quickly gaining popularity as the language to learn.
In 2011 a group of programmers started a project called Red. They were attempting to crete a so called full stack language. One language for web development, coding, applications right down to microprocessors.
They so wanted their language to be homioiconic, weakly typed and friendly to beginners. 3 years and a lot of work gave produced a language that's insightful and in depth, redefining the way we may program. They are still far from done though.
So, a full stack language is akin to the One Ring in Lord Of The Rings.
Looking at the current abilities of Javascript however, I think it coulld make a case for being an a ready to use full stack language.
JavaScript is
NodeJS was developed to allow programmers to write Javascript Applications for the server. With the proliferation of scripts that do a ton of things NodeJS can officially be used across the entire Stack.
MongoDB takes this a step further. This is a NoSQL database that allows you to program and query in Javascript.
There are a ton of development tools like Yeoman and Mean to help you take care of stuff.
So now we have a large part of the stack running with JS but its not yet Full Stack as per Red's definition
The reason its not yet full stack boils down to the hardware. We don't yet program our microprocessors in Javascript. But that too is changing in a big way.
These projects bring Javascript right down to the metal and allow you to program microcontrollers using it:
piJS is a project that allows you to program your Raspberry Pi in Javascript
Tessel and Espurino are custom microcontroller boards that are created specifically for the purpose of programming in Javascript
Though Javascript has a lot of detractors that haters repeat oft and loudly there are some serious benefits. Perhaps the most apparent benefit is that a ton ofn developers already know the language well. Javascript is quickly becoming the full stack language and that will probably benefit a lot of people.