2Building a website requires paying attention to the site’s information architecture, which might adopt a hierarchical, multidimensional, flat, or sequential structure. Usability should be assessed early, and the user interface should follow design principles that will make it easier for visitors to accomplish their goals on the site. The website should also support accessibility for people with disabilities. Software development for websites starts with HTML, the programming language used to format web pages. HTML 5 is the latest version that reduces problems for web developers, reduces the need for browser plug-ins like Flash, and adds new features, especially for mobile devices. Media-rich and interactive websites are created with other programming tools, such as JavaScript, AJAX, Flash, and programming languages that interface with back-end databases. Content management systems enable teams to work together on a website, offering simple ways to format content and providing support for version control and other features.