A Rich Internet Application (RIA) is a Web application that has many of the characteristics of desktop application software, typically delivered either by way of a site-specific browser, via a browser plug-in, independent sandboxes, extensive use of JavaScript, or virtual machines.[1] Adobe Flash, JavaFX, and Microsoft Silverlight are currently the three most common platforms, with desktop browser penetration rates around 96%, 76%, and 66% respectively (as of August 2011).[2] Mobile phone penetration of these plugins, however, has remained low even as internet traffic from these devices has grown. [3] Although new Web standards have emerged, they still use the principles behind RIAs.
Users generally need to install a software framework using the computer's operating system before launching the application, which typically downloads, updates, verifies and executes the RIA.[4] This is the main differentiator from JavaScript-based alternatives like Ajax that use built-in browser functionality to implement comparable interfaces. As can be seen on the List of rich Internet application frameworks which includes even server-side frameworks, while some consider such interfaces to be RIAs, some consider them competitors to RIAs; and others, including Gartner, treat them as similar but separate technologies.[5]
RIAs dominate in online gaming as well as applications that require access to video capture (with the notable exception of Gmail, which uses its own task-specific browser plug-in).[6] Web standards such as HTML5 have developed and the compliance of Web browsers with those standards has improved somewhat. However, the need for plug-in based RIAs for accessing video capture and distribution has not diminished,[7] even with the emergence of HTML5 and JavaScript-based desktop-like widget sets that provide alternative solutions for mobile Web browsing.
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The following platforms have over 50% market penetration on the desktop.[8]
Adobe Flash manipulates vector and raster graphics to provide animation of text, drawings, and still images. It supports bidirectional streaming of audio and video, and it can capture user input via mouse, keyboard, microphone, and camera. Flash contains an object-oriented language called ActionScript and supports automation via the JavaScript Flash language (JSFL). Flash content may be displayed on various computer systems and devices, using Adobe Flash Player, which is available free of charge for common web browsers, some mobile phones and a few other electronic devices (using Flash Lite).
Java applets are used both to create interactive visualisations and to present video, three dimensional objects and other media. Java applets are more appropriate for complex visualizations that require significant programming effort in high level language or communications between applet and originating server. Oracle's new JavaFX is considered as another competitor for Rich Internet Applications.
In recent years, Microsoft Silverlight has emerged as a potential competitor to Flash. While not yet as prevalent on websites as Flash, Silverlight has been used to provide video streaming for many high profile events, including the 2008 Summer Olympics in Beijing,[9] the 2010 Winter Olympics in Vancouver,[10] and the 2008 conventions for both major political parties in the United States.[11] Silverlight is also used by Netflix for its instant video streaming service.[12]
The term "rich Internet application" was introduced in a white paper of March 2002 by Macromedia (now merged into Adobe),[13] though the concept had existed for a number of years earlier under names such as:
Rich Internet applications use a Rich Client deployment model (deployment of a compiled client application through a browser) rather than a thin-client-server model (where the user's view is largely controlled from the server).
Flash, Silverlight and Java are application platforms accessed by the user's web browser as plug-ins. These application platforms limit the amount of data downloaded during initialization to only what is necessary to display the page. The browser plug-in is only downloaded once, and does not need to be re-downloaded every time the page is displayed; this reduces application load time, bandwidth requirements, and server load.
Proponents of RIAs assert that the cost of RIA development and O&M is typically lower than that of HTML-based alternatives due to increased developer productivity and standardized, backwards compatible nature of the application platform runtime environments. A 2010 study conducted by International Data Corporation demonstrated an average savings of approximately $450,000 per application in the case of Flash platform development (in conjunction with use of the open source Flex SDK), a 39% reduction in cost over a three-year period.[14]
RIAs present indexing challenges to Web search engines, but Adobe Flash content is now at least partially indexable.[15]
Security can improve over that of application software (for example through use of sandboxes and automatic updates), but the extensions themselves remain subject to vulnerabilities and access is often much greater than that of native Web applications. For security purposes, most RIAs run their client portions within a special isolated area of the client desktop called a sandbox. The sandbox limits visibility and access to the file-system and to the operating system on the client to the application server on the other side of the connection. This approach allows the client system to handle local activities, calculations, reformatting and so forth, thereby lowering the amount and frequency of client-server traffic, especially versus client-server implementations built around so-called thin clients.[16]
In November 2011 there were a number of announcements that demonstrated a decline in demand for rich internet application architectures. Adobe announced that Flash would no longer be produced for mobile[17] or TV[18] (refocusing its efforts on HTML 5). Pundits questioned its continued relevance even on the desktop[19] and described it as "the beginning of the end"[20]. RIM announced that it would continue to develop Flash for the PlayBook, a decision which has been described as "RIM's worst decision to date"[21]. Rumors state that Microsoft is to abandon Silverlight after version 5 is released[22]. The combination of these announcements had some proclaiming it "the end of the line for browser plug-ins"[23].
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