Home > Articles

Wireless Programming

This chapter is from the book

This chapter is from the book

In This Chapter


  • WAP/WML/WMLScript

  • Openwave SDK

  • i-mode

  • Java

  • .NET

  • In Chapters 1, "Wireless Hardware" and 2, "Wireless Network Protocols," we introduced wireless hardware and the 802.11 standard used in WLANs. Now that we've covered the infrastructure basics, let's briefly examine the wireless programming languages that facilitate communication on this infrastructure.

    Although basic wireless communication seems simple on the surface, the programming can be complex. Programmers must optimize everything for a device with minimal memory and processing power. Whether it is for ordering pizza, checking movie times and prices, or sending SMS messages, the code can be quite involved. In addition, the information must be accessible from a wide range of devices, such as cell phones, Blackberry units, and iPAQs. Each of these devices has its own proprietary hardware and software applications protocols.

    Programmers attacked this complex task with alacrity, and languages quickly evolved. Although the outcome is not completely standardized, the contestants have been narrowed down to a few stable and very useful languages. This chapter will examine the main types of programming and formatting found in handheld wireless devices. Currently the list includes the following:


    • WAP/WML/WMLScript

    • cHTML (i-mode)

    • Java (J2ME)

    • .NET


    We'll introduce wireless programming languages by first discussing the three markup languages. These include Hypertext Markup Language (HTML), Extensible Markup Language (XML), and the combination of the two, Extensible Hypertext Markup Language, (XHTML).


    HTML is the primary format used on the World Wide Web. HTML can display Web pages with a wide range of colors, shapes, and objects. Although not a true programming language, HTML has increased in power over the years.

    HTML is actually a loosely defined subset of XML. However, whereas XML is a strict language (as you will learn), HTML takes many liberties that have helped it become the popular presentation tool it is today. Although the spirit of the young Internet encouraged freedom, developers have now realized that the freedom of HTML has repercussions. Because HTML is so flexible, many browsers and Web applications have added their own functionality to the base HTML protocol. Like all enhanced functionality, this comes with additional security risks.

    For this reason, efforts are underway to replace HTML with a much more regulated and standardized markup language known as XHTML.


    XML is the foundation for many data formats, including HTML, WML, XHTML, and more. It has recently become popular because it can facilitate the transfer of data between widely disparate programs, operating systems, and companies. The key to XML's utility is that it enables any developer to design her own data format using her own terms and requirements. In fact, XML is so popular that Microsoft has built its entire suite of products, from operating systems to server components, around the concept of XML.

    To illustrate the utility of XML, let's consider a sample corporation that needs to share information about fruit inventory. Because direct access to a database would be a security risk (as well as poor business practice), the developer can create an XML program that defines the type, size, and color of each fruit on hand. Once she has determined the specs, the developer could program the host with the capability to pull data from a database and convert it to an XML file. On the other end, a special client could scan the generated XML file and parse the information to fill its own database. This process would thus allow for rapid and standardized data transfer.

    To illustrate this, consider the following sample source code to see how such an XML file would appear. Note the hierarchy and the matching set of labels. Each label is a property, which could have sub-properties. In this case, we are passing information about an apple and a grape.


    By extrapolating from this simple example, you can see how XML data is organized. The use of such relational data methods is still in its infancy, and will continue to grow for many years.

    Although XML is the foundation of many other Internet-based formatting languages, its subsets are giving XML the push it needs to become the de facto standard. A recent subset, XHTML, is slowly gaining ground, and is destined to overtake HTML in prevalence.


    Thus, XHTML will likely replace HTML. Although this process will take several years, many Webmasters have already embraced XHTML, and are slowly integrating its rules into their development. In fact, XHTML 1.0 is considered by many to be the next version of HTML (HTML 5.0).

    What makes XHTML so popular is its simple yet rigid ruleset. This ruleset is so powerful because it enforces a universal standard. The rules are as follows:

    • XHTML requires a declaration at the top of every XHTML page.

      This new rule tells the browser the type of data to render, which keeps all parts of the data presentation and transfer process flowing smoothly. The following is an example of an XHMTL declaration.

      <?xml version="1.0" encoding="UTF-8"?>
      <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
    • All XHTML pages must have the <head> and <body> tags.

      Although these tags typically exist in all Web pages, For HTML, Web browsers will overlook the missing data and fill it in automatically when it's not present. However, this is not the case with XHTML.

    • All tags must be closed.

      Prior to XHTML, Web pages included tags like <p>, which typically had a closing tag </p>. however, it didn't matter if the closing tag was left out. With XHTML, every tag must be closed. In addition, tags like "<HR>", which created a line across a Web page, must now look like <hr />. This is a completely new concept for Web pages.

    • All tags must be lower case.

      Again, this is a new rule. Previous versions of HTML used uppercase tags; now these tags must be lowercase. As you noticed the rule prior to this one, the <HR> not only gained a slash, but also became lowercase. (This only applies to tags, not attributes.)

    • All attributes must have quotes.

      Although this rule has traditionally been considered good coding practice, it is now mandatory. This will add complications for dynamically created Web pages.

    • All tags must be in the proper hierarchy (not nested).

      Again, this was considered good coding practice, but was not required. With XHTML, the following would no longer be correct:

      <I><B>Bolded and Italicized</I></B>

      Instead, it would now be written as follows:

      <i><b> Bolded and Italicized </b></i>

      (Note the lowercase letters.)

    • All attribute values must be denoted.

      This is not a common occurrence in HTML. However, if you are coding a group of radio buttons, one might be listed as "checked." See the following old versus new way of listing this:


      New: <input type="radio" checked="true" name="AnyName"/>

      (Note the use of lowercase, quotes, and a closing slash.)

    • All <pre> tags must not contain the following tags:

      <big>, <small>, <sub>, <sup>, <img>, or <object>

    • Form cannot be nested.

    • All "&" symbols must be written as "&amp;".

    • All CSS must be written in lowercase letters.

    • All JavaScript must be performed externally.

      JavaScript is a programming language, and is separate from XHTML, which is only a formatting language. Remember, XHTML is ONLY FOR PRESENTATION (with CSS).

      In addition, JavaScript is not commented out.

    • All <!-- comments --> are illegal.

      Of course, commenting is still supported in XHTML, if it is performed with the following syntax:

      <[CDATA[comments appear in here]]>

    By contrasting these simple but powerful rules with HTML, you can begin to see the advantages of XHTML. In addition, PCS (Personal Communication Service) devices also use XHTML. Because of the myriad of vendors, each with its own proprietary approach, the strict rules of XHTML and XML are vital. Without this standard, Web developers would have to create separate Web pages for each device. Fortunately, because of this standard, developers can create one or two pages for all devices. However, XHTML is still too bloated for many smaller PCS devices. Therefore, another option is required.

    InformIT Promotional Mailings & Special Offers

    I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


    Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

    This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

    Collection and Use of Information

    To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

    Questions and Inquiries

    For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

    Online Store

    For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


    Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

    Contests and Drawings

    Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


    If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

    Service Announcements

    On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

    Customer Service

    We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

    Other Collection and Use of Information

    Application and System Logs

    Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

    Web Analytics

    Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

    Cookies and Related Technologies

    This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

    Do Not Track

    This site currently does not respond to Do Not Track signals.


    Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


    This site is not directed to children under the age of 13.


    Pearson may send or direct marketing communications to users, provided that

    • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
    • Such marketing is consistent with applicable law and Pearson's legal obligations.
    • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
    • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

    Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

    Correcting/Updating Personal Information

    If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


    Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

    Sale of Personal Information

    Pearson does not rent or sell personal information in exchange for any payment of money.

    While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

    Supplemental Privacy Statement for California Residents

    California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

    Sharing and Disclosure

    Pearson may disclose personal information, as follows:

    • As required by law.
    • With the consent of the individual (or their parent, if the individual is a minor)
    • In response to a subpoena, court order or legal process, to the extent permitted or required by law
    • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
    • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
    • To investigate or address actual or suspected fraud or other illegal activities
    • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
    • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
    • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


    This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

    Requests and Contact

    Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

    Changes to this Privacy Notice

    We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

    Last Update: November 17, 2020