Waiting for an organisation to agree a technical description of a computer language that has been widely used may seem over-cautious but adhering to agreed standards will increase the accessibility, reliability and effectiveness of a multimedia publication. Agreed standards are publicly available at the International Organisation for Standardisation (ISO) and the World Wide Web Consortium.

Language standards

HTML and DHTML
HTML has been described in Section 2 on Multimedia. 'Vanilla' html refers to html that strictly adheres to the standards set down by the World Wide Web Consortium. When producing HTML, the designer or programmer should be aware that commercial browsers have their own extensions to the language, such as DHTML. Testing on all the target user environments is essential. The W3C website has information and programs that validate html to the various standards. The source code is available to download or there is a form to check a particular url at http://validator.w3.org/. The minimum standard is currently version html 3.2 (see the IPG for the most up-to-date information). DHTML, dynamic HTML, is the marketing term for the use of cascading style sheets (CSS-1) with html and the various add-on scripting languages (JavaScript/JScript/VBScript/ECMAScript) implemented by commercial browsers. In short, dhtml enhances the developer's ability to affect the appearance of the pages to the user. More information on style sheets is available from the World Wide Web Consortium or various web and printed sources.

NB: When using DHTML/CSS in html production, you should be aware that these might or might not have the same result on different browsers. dhtml or css implemented in VBScript will not be displayed correctly using Netscape Navigator. It is best to follow the recommendations of the World Wide Web Consortium to ensure future across-the-board compatibility.

SGML and XML
Standard generalised mark-up language (SGML) is a standard for specifying a document mark-up language or tag set. html is an example of an SGML-based language developed to be a simple mark-up language for the web. Extensible mark-up language (XML) is a structured set of rules on defining data to be shared on the web. html allows the mark-up of a manuscript with an indication of how it should be shown but xml means you can invent your own tags to indicate the type of data that is being sent. Providing that both the sender and receiver know about use of these tags, the code can be dealt with in a predefined manner. XHTML is the World Wide Web Consortium's effort to merge the possibilities of xml into HTML. Specific sets of extensions for XHTML are planned for mathematical expressions, Vector graphics, and multimedia applications. The possibility to customise tags has specific implications for devices other than the traditional PC and browser. For example, special tags understood by a client's watch mean the watch could indicate and display E-mail. More examples and explanations can be found at http://www.wdvl.com/Authoring/Languages/XML/XHTML/.

JAVA
Java is a language originally designed for use on the Internet. Java-compiled code is designed to run on a Java-virtual machine. In this way, the code can be run by any machine incorporating a Java-virtual machine. Both the major web browsers have a virtual machine embedded, making a large possible user base for java Applets. The possibility of putting virtual machines in other environments, such as a car, adds to the opportunities for using java in the future. java has strong networking support, which makes it a strong candidate for use in the hybrid multimedia environment. However, java is sometimes described as being too heavy or slow in multimedia development. java can be found at http://java.sun.com.

SMIL
Synchronised multimedia integration language (SMIL 1.0, pronounced 'smile') permits integration of a set of independent multimedia objects into a synchronised multimedia presentation. SMIL is an easy-to-learn HTML-like language and, for this reason, SMIL presentations can be written using a text-editor. A SMIL presentation can be composed of streaming audio, streaming video, images, text or any other media type. SMIL is specified by the World Wide Web Consortium.
SMIL can be used to:

• describe the temporal behaviour of the presentation
  
• describe the layout of the presentation on a screen
  
• associate hyperlinks with media objects.