473,401 Members | 2,125 Online
Bytes | Software Development & Data Engineering Community
Post Job

Home Posts Topics Members FAQ

Join Bytes and contribute your articles to a community of 473,401 developers and data experts.

Intro to WML - WAP Basics #1

5,000 Expert 4TB
Originally published on www.developer.com/ws/proto/article.php/1377381

Edited by RedSon

Learning WML - WAP Basics
By Steve Schafer
June 26, 2002

What Is WAP?

WAP stands for Wireless Access Protocol, a general term used to describe the multi-layered protocol and related technologies that bring Internet content to mobile devices such as PDAs and cell phones.

Such devices are referred to as thin clients because they have one or more constraints in the form of display, input, memory, CPU, or other hardware or usability limitations. The platform constraints and the slower (and more expensive) bandwidth of cellular and related networks make standard Internet protocols difficult to utilize. Using the growing set of WAP tools and protocols, however, the mobile Internet is quite a capable tool.

A Brief History of WAP

As previously stated, WAP refers to a wide range of technologies and protocols, all related to mobile Internet functionality. This functionality has roots dating back to the mid 1990s. At that time, several vendors were working on the mobile Internet problem as mobile device sales skyrocketed, and several competing technologies emerged:

* Nokia's Narrow Band Sockets (NBS) and Tagged Text Markup Language (TTML)
* Ericsson's Intelligent Terminal Transfer Protocol (ITTP)
* Unwired Planet's Handheld Device Markup Language (HDML)

Each technology had its own purpose, but some overlapped with others in various areas. This diversity threatened to fragment the wireless industry along provider lines. In mid 1997, the WAP Forum was founded to aid in communication among the developers and to spur a common set of protocols and technologies. In the same year, the industry took another step forward with the formation of the Open Mobile Alliance (OMA), which combined several distinct development and standards bodies into one.

How Does WAP Work?

These articles will focus on the delivery of WML content to mobile devices over a cellular or related technology network. However, the delivery of many protocols and technologies takes the same route-namely, through a proxy server that bridges the gap between the wired Internet and the wireless service provider's network.

The proxy server manages the communication between the wireless client and the Internet server(s), acting as a gateway to the wired Internet. It caches content and in some cases even translates raw HTML into WAP-compatible protocols such as WML.

Many mobile devices have a built-in wireless browser. Although several different browsers are in use today among the various wireless providers, most browsers support WML, either natively or translated into HDML. A popular precursor to WML, the Handheld Device Markup Language (HDML), is still supported on several mobile platforms. However, due to the limitations of HDML (supporting only a handful of navigation tags and virtually no formatting tags), WML is becoming the most widely used mobile markup language. That said, if you plan to support a particular platform, it's best to test your code extensively on that particular device.
Note: When coding for the general public, be careful to stick to the standards and avoid using proprietary extensions to the various languages, no matter how tempting the feature set of the extensions. If you decide to provide the extensions to those who can use them, you should take the necessary server steps to identify the connecting browser and deliver code customized for that browser.

What Is WML?

WML (Wireless Markup Language) is the dominant language in use with wireless devices today. Essentially, WML is a subset of HTML, but has its roots in XML. Those developers with a solid base in XML should have a relatively easy time coding WML.

There are several key differences between WML and standard HTML, including the following:

* WML is highly structured and very particular about syntax. Several current HTML browsers allow for "messy" code such as missing tags and other formatting snafus. Such mistakes are not allowed in WML; the mobile browser will complain and generally won't display the page.

* WML is case sensitive. The tags <b> and <B> are treated as different tags, although they accomplish the same purpose (bold text). Therefore, you must be careful to match the case of your opening tags with your closing tags (for example, <b>This is bold</B> will not work as expected).

* Many tags have required attributes. Developers accustomed to HTML may be used to including only attributes they need-in some WML tags, you must include a few attributes, even if they are blank or default.

* WML pages are structured in "decks", allowing for multiple pages to be defined in each WML file.

WML also has a client-side scripting language, WMLScript, to help automate particular tasks, validate input, and so on. WMLScript is a subset of JavaScript.

Stay tuned for the next bit of this in the following week!
Feb 22 '07 #1
0 6939

Sign in to post your reply or Sign up for a free account.

Similar topics

by: Kamus of Kadizhar | last post by:
I'm looking for a good intro to python book. I'm very familiar with programming, but know nothing of OOP or systems (OS type) programming. All of my programming experience is in number crunching...
by: manish | last post by:
Hi, I am a fresher in the programming field i.e although I have done programming at the basic level but at professional level I am very new and I am facing many problems. These probllems are...
by: Alf P. Steinbach | last post by:
The third part of my attempted Correct C++ tutorial is now available, although for now only in Word format (use free Open Office if no Word), and also, it's not yet been extensively reviewed -- ...
by: Chad | last post by:
I'm in an intro to VB.net class. I'm haveing trouble with this assignment, if anyone could help me please let me know. thanks! Coding Assignment 7-Chapter 8 OOP-CSCI-171 Intro to VB.NET ...
by: Guy Middleton | last post by:
A friend want to learn C, and is already an experienced programmer -- she knows VB and Java, and some application-specific HLLs (e.g. ToolBook). Could somebody recommend an intro C text I could...
by: shapper | last post by:
Hello, When styling a DIV as follows: <div id="intro" class="Intro">Some intro text</div> Should I use a class: ..Intro {...} Or:
by: annabel59 | last post by:
I made a Flash intro for my website but when I open it in IE7 it gives error : expected object. It works fine in Mozilla. This is the code of the index.html file : <html> <head>...
by: babu8880 | last post by:
www.convensysglobal.com/elearn You can login and attend courses and similar resources ask your doubts from experienced engineers in iphone and Objective C Domain You can attend live classes...
by: emmanuelkatto | last post by:
Hi All, I am Emmanuel katto from Uganda. I want to ask what challenges you've faced while migrating a website to cloud. Please let me know. Thanks! Emmanuel
by: BarryA | last post by:
What are the essential steps and strategies outlined in the Data Structures and Algorithms (DSA) roadmap for aspiring data scientists? How can individuals effectively utilize this roadmap to progress...
by: Sonnysonu | last post by:
This is the data of csv file 1 2 3 1 2 3 1 2 3 1 2 3 2 3 2 3 3 the lengths should be different i have to store the data by column-wise with in the specific length. suppose the i have to...
by: Hystou | last post by:
There are some requirements for setting up RAID: 1. The motherboard and BIOS support RAID configuration. 2. The motherboard has 2 or more available SATA protocol SSD/HDD slots (including MSATA, M.2...
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can...
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows...
by: tracyyun | last post by:
Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each...
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing,...
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.