M-Commerce Wireless Markup Language (WML) By Prof T.R. Vaidyanathan

Wireless Markup Language(WML) Wireless Markup Language, based on XML, is a markup language intended for devices that implement the Wireless Application Protocol (WAP) specification, such as mobile phones, and preceded the use of other markup languages now used with WAP, such as HTML / XHTML (which are gaining in popularity as processing power in mobile devices increases). WML is the language used to create pages to be displayed in a WAP browser.

Wireless Markup Language(WML) WAP is used to create a Gateway that serves as a two-way intermediary connecting path between the Internet and a mobile phone. The Gateway fetches the WML program from the remote server, compiles it, and sends the compiled byte stream to the wireless browser.

Wireless Markup Language(WML) WML is designed to allow the static display of text, tables, hyperlinks, monochrome images, and input fields. The individual page is called a card, and a collection of these cards which are linked together is referred to as a deck. There is usually an upper size limit (typically 1400 bytes compiled) for a card.

Wireless Markup Language(WML) WML is similar to HTML. However, WML borrows heavily from the constructs of the Extensible Markup Language (XML) – the internet successor to HTM. The creators of WML accounted for the limited resources of WAP devices. WML was formed to create the global wireless protocol specification that works across differing wireless network technology types, for adoption by appropriate industry standards bodies.

Wireless Markup Language(WML) WML is designed with the constraints of small narrowband devices in mind. These constraints include: 1) Small display and limited user input facilities; 2) Narrowband network connection; 3) Limited memory and computational resources.

Wireless Markup Language(WML) Both WML and HTML render similarly in their respective browsers. WAP browsers are just much more screen size challenged. WML as a language has the following general features. Support for Text – this includes presentation hints like line breaks, formatting(bold, italic and emphasis), and other placement clues Support for user input – WML includes text entry fields, choice lists, and controls that invoke tasks. For instance, you can assign a URL to a specific button on a device such at when the user presses the button, a request is sent for a new document. .

Wireless Markup Language(WML) A variety of navigation mechanisms _ Based on the Internet-standard URL naming scheme, WAP lets you move between documents. Each WAP device may also incorporate a history mechanism for documents already visited, so that the user can revisit a previous document just by pressing a Back button, much like revisiting a previous page in a web browser. Support for multiple languages and dialects – WML provides support for multiple languages and dialects by using the 16-bit Unicode character set State and context management features – State management implies that variable values can be passed from document to document. Additional capabilities include variable substitution and caching of variables and documents to maximize cache hits on the device and minimize wireless server requests

WMLScript There is a companion language called WMLScript that can be used to create functions for WML pages. This adds some versatility to WML. Again, as a first approximation, WMLScript is to WML as JavaScript is to HTML, and is part of the Wireless Application Protocol (WAP).

WMLScript Just like JavaScript, WMLScript is used for the following tasks: User input validation-As user enter data like their name, rupee amount, or a phone number, WMLScript can validate the input against some templates. For example, it can check that the rupee amount entered is under 100 and includes two digits after the decimal. User Interaction. WMLScript lets an application interact constantly needing to contact a Web Server for more documents. Its capability lets the program logic decide which document to show next or display an error message of some sort without going over the network. It includes libraries that provide a wide range of functionality, including math calculations, string processing, and so on