White Paper on Programming with JavaScript
COURTESY :- vrindawan.in
Wikipedia
A white paper is a report or guide that informs readers concisely about a complex issue and presents the issuing body’s philosophy on the matter. It is meant to help readers understand an issue, solve a problem, or make a decision. A white paper is the first document researchers should read to better understand a core concept or idea.
The term originated in the 1920s to mean a type of position paper or industry report published by some department of the UK government.
Since the 1990s, this type of document has proliferated in business. Today, a business-to-business (B2B) white paper is closer to a marketing presentation, a form of content meant to persuade customers and partners and promote a certain product or viewpoint. That makes B2B white papers a type of grey literature.
The term white paper originated with the British government and many point to the Churchill White Paper of 1922 as the earliest well-known example under this name. Gertrude Bell, the British explorer and diplomat, was possibly the first woman to write a white paper. Her 149-page report was entitled “Review of the Civil Administration of Mesopotamia” and was presented to Parliament in 1920. In the British government, a white paper is usually the less extensive version of the so-called blue book, both terms being derived from the colour of the document’s cover.
White papers are a “tool of participatory democracy … not [an] unalterable policy commitment”. “White papers have tried to perform the dual role of presenting firm government policies while at the same time inviting opinions upon them.
In Canada, a white paper is “a policy document, approved by Cabinet, tabled in the House of Commons and made available to the general public”. The “provision of policy information through the use of white and green papers can help to create an awareness of policy issues among parliamentarians and the public and to encourage an exchange of information and analysis. They can also serve as educational techniques.”
White papers are a way the government can present policy preferences before it introduces legislation. Publishing a white paper tests public opinion on controversial policy issues and helps the government gauge its probable impact.
By contrast, green papers, which are issued much more frequently, are more open-ended. Also known as consultation documents, green papers may merely propose a strategy to implement in the details of other legislation, or they may set out proposals on which the government wishes to obtain public views and opinion.
Examples of governmental white papers include, in Australia, the White Paper on Full Employment and, in the United Kingdom, the White Paper of 1939 and the 1966 Defence White Paper.
Ajax is not a technology, but rather a programming concept. HTML and CSS can be used in combination to mark up and style information. The web page can be modified by JavaScript to dynamically display—and allow the user to interact with the new information. The built-in XML Http Request object is used to execute Ajax on web pages, allowing websites to load content onto the screen without refreshing the page. Ajax is not a new technology, nor is it a new language. Instead, it is existing technologies used in a new way.
In the early-to-mid 1990s, most Websites were based on complete HTML pages. Each user action required a complete new page to be loaded from the server. This process was inefficient, as reflected by the user experience: all page content disappeared, then the new page appeared. Each time the browser reloaded a page because of a partial change, all the content had to be re-sent, even though only some of the information had changed. This placed additional load on the server and made bandwidth a limiting factor in performance.
In 1996, the iframe tag was introduced by Internet Explorer; like the object element, it can load or fetch content asynchronously. In 1998, the Microsoft Outlook Web Access team developed the concept behind the XML Http Request scripting object. It appeared as XML HTTP in the second version of the MSXML library, which shipped with Internet Explorer 5.0 in March 1999.
The functionality of the Windows XML HTTP ActiveX control in IE 5 was later implemented by Mozilla Firefox, Safari, Opera, Google Chrome, and other browsers as the XML Http Request JavaScript object. Microsoft adopted the native XML Http Request model as of Internet Explorer 7. The ActiveX version is still supported in Internet Explorer, but not in Microsoft Edge. The utility of these background HTTP requests and asynchronous Web technologies remained fairly obscure until it started appearing in large scale online applications such as Outlook Web Access (2000) and Odd post (2002).
Google made a wide deployment of standards-compliant, cross browser Ajax with Gmail (2004) and Google Maps (2005). In October 2004 Kayak.com’s public beta release was among the first large-scale e-commerce uses of what their developers at that time called “the xml http thing”. This increased interest in Ajax among web program developers.
The term AJAX was publicly used on 18 February 2005 by Jesse James Garrett in an article titled Ajax: A New Approach to Web Applications, based on techniques used on Google pages.
On 5 April 2006, the World Wide Web Consortium (W3C) released the first draft specification for the XML Http Request object in an attempt to create an official Web standard. The latest draft of the XML Http Request object was published on 6 October 2016, and the XML Http Request specification is now a living standard.
The term Ajax has come to represent a broad group of Web technologies that can be used to implement a Web application that communicates with a server in the background, without interfering with the current state of the page. In the article that coined the term Ajax, Jesse James Garrett explained that the following technologies are incorporated:
- HTML (or XHTML) and CSS for presentation
- The Document Object Model (DOM) for dynamic display of and interaction with data
- JSON or XML for the interchange of data, and XSLT for XML manipulation
- The XML Http Request object for asynchronous communication
- JavaScript to bring these technologies together
Since then, however, there have been a number of developments in the technologies used in an Ajax application, and in the definition of the term Ajax itself. XML is no longer required for data interchange and, therefore, XSLT is no longer required for the manipulation of data. JavaScript Object Notation (JSON) is often used as an alternative format for data interchange, although other formats such as preformatted HTML or plain text can also be used. A variety of popular JavaScript libraries, including JQuery, include abstractions to assist in executing Ajax requests.
JavaScript is a high-level, often just-in-time compiled language that conforms to the ECMAScript standard. It has dynamic typing, prototype-based object-orientation, and first-class functions. It is multi-paradigm, supporting event-driven, functional, and imperative programming styles. It has application programming interfaces (APIs) for working with text, dates, regular expressions, standard data structures, and the Document Object Model (DOM).
The ECMAScript standard does not include any input/output (I/O), such as networking, storage, or graphics facilities. In practice, the web browser or other runtime system provides JavaScript APIs for I/O.
JavaScript engines were originally used only in web browsers, but are now core components of some servers and a variety of applications. The most popular runtime system for this usage is Node.js.
Although Java and JavaScript are similar in name, syntax, and respective standard libraries, the two languages are distinct and differ greatly in design.
The first web browser with a graphical user interface, Mosaic, was released in 1993. Accessible to non-technical people, it played a prominent role in the rapid growth of the nascent World Wide Web. The lead developers of Mosaic then founded the Netscape corporation, which released a more polished browser, Netscape Navigator, in 1994. This quickly became the most-used.
During these formative years of the Web, web pages could only be static, lacking the capability for dynamic behavior after the page was loaded in the browser. There was a desire in the flourishing web development scene to remove this limitation, so in 1995, Netscape decided to add a scripting language to Navigator. They pursued two routes to achieve this: collaborating with Sun Micro systems to embed the Java programming language, while also hiring Brendan Eich to embed the Scheme language.
Netscape management soon decided that the best option was for Eich to devise a new language, with syntax similar to Java and less like Scheme or other extant scripting languages. Although the new language and its interpreter implementation were called Live Script when first shipped as part of a Navigator beta in September 1995, the name was changed to JavaScript for the official release in December.
The choice of the JavaScript name has caused confusion, implying that it is directly related to Java. At the time, the dot-com boom had begun and Java was the hot new language, so Eich considered the JavaScript name a marketing ploy by Netscape.
Microsoft debuted Internet Explorer in 1995, leading to a browser war with Netscape. On the JavaScript front, Microsoft reverse-engineered the Navigator interpreter to create its own, called J Script.
J Script was first released in 1996, alongside initial support for CSS and extensions to HTML. Each of these implementations was noticeably different from their counterparts in Navigator. These differences made it difficult for developers to make their websites work well in both browsers, leading to widespread use of “best viewed in Netscape” and “best viewed in Internet Explorer” logos for several years.
In November 1996, Netscape submitted JavaScript to Ecma International, as the starting point for a standard specification that all browser vendors could conform to. This led to the official release of the first ECMAScript language specification in June 1997.
The standards process continued for a few years, with the release of ECMAScript 2 in June 1998 and ECMAScript 3 in December 1999. Work on ECMAScript 4 began in 2000.
Meanwhile, Microsoft gained an increasingly dominant position in the browser market. By the early 2000s, Internet Explorer’s market share reached 95%. This meant that JScript became the de facto standard for client-side scripting on the Web.
Microsoft initially participated in the standards process and implemented some proposals in its JScript language, but eventually it stopped collaborating on Ecma work. Thus ECMAScript 4 was mothballed.