With so many different Web operating systems either currently available or in development, it should come as no surprise that programmers use different approaches to achieve the same effect. While the goal of a Web OS is to provide an experience similar to using a desktop OS, there are no hard and fast rules for how to make that happen. The two most popular approaches rely on Flash technologies or Asynchronous JavaScript and XML (AJAX) technologies.
Flash is a set of technologies that enable programmers to create interactive Web pages. It's a technology that uses vector graphics. Vector graphics record image data as a collection of shapes and lines rather than individual pixels, which allows computers to load Flash images and animation faster than pixel-based graphics.
Flash files stream over the Internet, which means the end user accessing the file doesn't have to wait for the entire file to download to his or her computer before accessing parts of it. With Flash-based programs like YouTube's video player, this means you can start watching a film clip without having to download it first.
More than 98 percent of all computers connected to the Internet have a Flash player installed [source: Adobe]. That makes Flash an attractive approach for many programmers. They can create a Web OS knowing that the vast majority of computer users will be able to access it without having to download additional software.
AJAX technologies rely on hypertext markup language (HTML), the JavaScript programming language, Cascading Style Sheets (CSS) and eXtensible Markup Language (XML). It's a browser technology. The HTML language is a collection of markup tags programmers use on text files that tell Web browsers how to display the text file as a Web page. CSS is a tool that gives programmers more options when tweaking a Web site's appearance. Programmers can create a style sheet with certain attributes such as font style and color, and then apply those styles across several Web pages at once. JavaScript is a programming language that allows applications to send information back and forth between servers and browsers. XML is a markup language, which means programmers use it to describe the structure of information within a file and how it relates to other information.
The "asynchronous" aspect of AJAX means that AJAX applications transfer data between servers and browsers in small bits of information as needed. The alternative is to send an entire Web page to the browser every time something changes, which would significantly slow down the user's experience. With sufficient skill and knowledge, a programmer can create an AJAX application with the same functions as a desktop application.
Like Flash, most computers can run AJAX applications. That's because AJAX isn't a new programming language but rather a way to use established Web standards to create new applications. As long as an application programmer includes the right information in an application's code, it should run fine on any major Web browser. Some well known Web applications based on AJAX include Google Calendar and Gmail.
Why would anyone want to use a Web OS? Keep reading to find out.