Using HTML5 and JavaScript
You don't need a professional development environment such as Xcode or Microsoft® Visual Studio® to write HTML5 and JavaScript code. Most modern browsers include sophisticated developer features including HTML and JavaScript debuggers. You can literally write your application in a text editor and test it in a browser. However, you do need a good knowledge of popular industry libraries that can help to minimize your coding effort.
The recent growth in mobile development has led to an explosion of new web technology toolkits. Often, these JavaScript libraries are open-source and don't require licensing. Most of the tools provided by Salesforce for HTML5 development are built on these third-party technologies.