Mustache can be used to deal with templating. Not only in JavaScript, Mustache is available for many languages including Nustache for .NET and mustache sharp for C#.
There are other client side templating options available, such as HandleBars an UnderscoreJS.
Why use client side JavaScript templating?
http://www.smashingmagazine.com/2012/12/05/client-side-templating/
http://en.wikipedia.org/wiki/JavaScript_templating
https://www.google.lk/search?q=why%20use%20client%20side%20templating
Resources
http://coenraets.org/blog/2011/12/tutorial-html-templates-with-mustache-js/
http://stackoverflow.com/questions/10555820/what-are-the-differences-between-mustache-js-and-handlebars-js
http://stackoverflow.com/questions/10555820/what-are-the-differences-between-mustache-js-and-handlebars-js
