B211 Lab Week 11

Laboratory Week 11 - Example XML Applications

Learning Objectives:

Have a basic appreciation of how XML is currently used.

Before doing the tutorial, please read:

Week 7 lecture on XML.

Software required:

This lab requires use of Netscape Navigator 4.x or Microsoft Internet Explorer 5.0+ web browsers, and a SMIL browser/player such as RealNetworks' RealPlayer. If you do not have a SMIL player, you may download a free copy of RealPlayer from the RealNetworks web site.

Instructions and Exercises:

Most of the XML software and information you find on the web are geared towards XML developers. Unless you have done extra studies on XML, most of the information will not be relevant for you. The aim of this laboratory is to give you an basic appreciation of the use of XML, by looking at two example XML applications (ie. two mark-up languages created using XML). If you choose to go beyond this basic introductions, you may enrol in B336 Advanced Internet Computing in the future.

Synchronized Multimedia Integration Language (SMIL)

SMIL (pronounced "smile") is a mark-up language created for defining how various audio-visual elements should be synchronized in a presentation. To look at an example SMIL document, and then to display it, do the following:

Click here to see an example SMIL document in text (select View>Source in your browser after opening the page if using IE). This example came from an online tutorial which uses animation and sounds to demonstrate SMIL. Note that the document text looks like HTML, but starts with <?xml?> and <smil> instead of <html>. There are also SMIL specific tags such as <par> (present in parallel), <seq> (present in sequence), etc.

Now check if your browser is equiped to handle .smil files. In Netscape Navigator, look at the Edit>Preferences>Category:Navigator>Applications and make sure there is an entry for "SMIL file" or "SMIL document". For IE5, you have to start up the Windows Explorer application and look under View>Folder Options>File Types (different Windows versions have it in slightly different menu items - just look for File Types).

If there is no entry, then you will have to install a SMIL player, such as RealNetworks' RealPlayer. You may download a free copy of RealPlayer from the RealNetworks web site.

Note: This check is only necessary for students doing their work externally. Internal labs already have the SMIL player set correctly.

Now click here access the example SMIL file in (1) properly using your browser. Your browser should start up the SMIL player and start playing the audio-visual stream (the sound starts up after about 30 seconds after the animation begins).

Of course, RealPlayer is not the only software that can display SMIL files. You can get a list of software from the official SMIL website at W3C. Other SMIL software also include authoring tools, which allows you to generate SMIL files (similar to Macromedia Dreamweaver or Microsoft FrontPage for HTML files).

Mathematical Markup Language (MathML)

MathML is a mark-up language created for representing mathematical and scientific notations. We will try doing what we did with SMIL:

Click here to see what the MathML file looks like in text.

Click here to see an image of what a MathML browser should show you.

Now using Microsoft IE5 (do not use Netscape Navigator), click here to see what the browser is capable of showing you. IE shows you the XML document in a tree form. You can click on the various sections to expand/collapse the tree branches. Compare the representation to the original document.
In this case, the browser do not know what the elements in the XML file is, and therefore the best that it can do is show the structure. Netscape Navigator 4.x doesn't even understand XML files, and Navigator 6 only displays all the text inside of the tags, without a tree structure.

For a list of available MathML browsers and software, look at the MathML website.

In the future, the more popular user-oriented XML applications (ie. the languages defined in XML), such as SMIL above, will probably be supported by popular browsers in one way or another. For the less popular ones, users will download separate browsers and software to deal with them.

Remember to read the week's development on the Internet by scanning through relevant articles in the IT section of Tuesday's the Australian newspaper - use the online version or the physical copy in the University library. Get into the habit of keeping up with current developments. Test your knowledge of major developments by going through the Good News Week self-tests.

H.L. Hiew
Unit Coordinator