Over the past years, web development processes have been improved incredibly with the fact that websites and web applications became extremely useful and beneficial in several different areas such as business, education, e-commerce, entertainment etc. At the same time, web development tools and technologies have been improved to be able to develop more creative and interactive websites and web applications. Therefore, a wide variety of methods, tools and languages for developing websites and web applications are available for the web developers nowadays. In this thesis, JavaScript among all of the web development technologies is analyzed with the hope of contributing web development processes. A prototype named JS_Librarian has been developed for this thesis with the purpose of collection and classification of JavaScript libraries included in websites. The application accepts website URLs as input. After it receives URLs, it makes request to the webpages of the website and retrieves the HTML code. Then JavaScript code is extracted from the HTML code, so the basic process of information retrieval is achieved in this way. After the information retrieval process, JavaScript codes are analyzed and selected classification methods are applied to the URLs that are residing in the system. At the end of the study, JavaScript libraries have been classified based on specified website categories and the retrieval reports from the application represents that class of JavaScript libraries used in websites may vary according to categories of websites.