application frameworks and Web template systems are available for general-use programming languages like Perl, PHP, Python and Ruby to make it faster and easier to create complex dynamic websites. A site can display the current state of a dialogue between users, monitor a changing situation, or provide information in some way personalized to the requirements of the individual user. For example, when the front page of a news site is requested, the code running on the webserver might combine stored HTML fragments with news stories retrieved from a database or another website via RSS to produce a page that includes the latest information. Dynamic sites can be interactive by using HTML forms, storing and reading back browser cookies, or by creating a series of pages that reflect the previous history of clicks. Another example of dynamic content is when a retail website with a database of media products allows a user to input a search request, e.g. for the keyword Beatles. In response, the content of the Web page will spontaneously change the way it looked before, and will then display a list of Beatles products like CDs, DVDs, and books. Dynamic HTML uses JavaScript code to instruct the Web browser how to interactively modify the page contents. One way to simulate a certain type of dynamic website while avoiding the performance loss of initiating the dynamic engine on a per-user or per-connection basis is to periodically automatically regenerate a large series of static pages. Multimedia and interactive content Early websites had only text, and soon after, images. Web browser plug-ins were then used to add audio, video, and interactivity (such as for a rich Web application that mirrors the complexity of a desktop application like a word processor). Examples of such plug-ins are Microsoft Silverlight, Adobe Flash Player, Adobe Shockwave Player, and Java SE. HTML 5 includes provisions for audio and video without plugins. JavaScript is also built into most modern web browsers, and allows for website creators to send code to the web browser that instructs it how to interactively modify page content and communicate with the web server if needed. The browser's internal representation of the content is known as the Document Object Model (DOM). WebGL (Web Graphics Library) is a modern JavaScript API for rendering interactive 3D graphics without the use of plug-ins. It allows interactive content such as 3D animations, visualizations and video explainers to