Dynamic Documents

Recent browsers (i.e. Netscape and the Internet Explorer) support various mechanisms for introducing dynamic content into previously static HTML documents.

Dynamic HTML
New for the v4.0 browsers, is Dynamic HTML. Expansive extensions to the scripting Object Models of both browsers mean that largely all content is now available to scripting functions (Internet Explorer takes Dynamic HTML to an extreme level, making everything in the document available). See the Dynamic HTML Overview for more information.

Server push
The server sends down a chunk of data; the browser display the data but leaves the connection open; whenever the server wants it sends more data and the browser displays it, leaving the connection open; at some later time the server sends down yet more data and the browser displays it; etc.

Client pull
The server sends down a chunk of data, including a directive (in the HTTP response or the document header) that says "reload this data in 5 seconds", or "go load this other URL in 10 seconds". After the specified amount of time has elapsed, the client loads the given URL.

Netscape Navigator 2.0 and Netscape Navigator Gold 2.0 (and above) and Internet Explorer provide flexible, lightweight programmability via the Netscape scripting language, a programmable API that allows cross-platform scripting of events, objects, and actions. It allows the page designer to access events such as startups, exits, and user mouse clicks. Based on the Java language, the Netscape scripting language extends the programmatic capabilities of Netscape Navigator to a wide range of authors and is easy enough for anyone who can compose HTML. Use the Netscape scripting language to glue HTML, inline plug-ins, and Java Applets to each other. Note : Recently, Netscape presented Javascript 1.1 to the ECMA, where it has evolved into ECMAScript (or rather ECMA-262), "A general purpose, cross-platform programming language". Netscape then proceeded to make extensions to Javascript, which became Javascript 1.2 as supported in the Navigator component of Netscape Communicator. Microsoft's JScript (v3.0 of which ships with Internet Explorer 4.0 is currently the only full implementation of ECMAScript. All Javascript 1.2 extensions are also supported by Internet Explorer 4.0 through its enhanced scripting object model.

From Sun Microsystems comes Java, the platform independent programming language for creating executable content within web pages. Based on C++, this is not a language to be taken lightly, but when mastered, could prove as limitless as the authors imagination. Indeed, some have even gone so far as to predict that the computer software industry is seriously under threat, because in a few years, all applications will be in the form of applets, downloaded as and when they are required.

The recent technology from Microsoft based around ActiveX controls (previously known as OLE controls). A new control requirement specification has meant that OLE controls previously burdened with code inappropriate for use on the Internet can now be much more streamlined, making it possible to embed them as <OBJECT>s into web pages. This (like Java) allows almost limitless activity and interactivity within web pages. (Internet Explorer for Windows 95/NT specific)

Visual Basic Script
A lightweight, yet fully compatible version of Visual Basic, designed for use on the Internet, Visual Basic Script allows full automation, customisation and scripting within web pages. Coming into its own when used to control ActiveX controls, Of all the available methods for creating dynamic content, Visual Basic Script is the easiest to learn. (Internet Explorer for Windows 95/NT specific)

Server Side Includes
Server side includes (SSI) applied to an HTML document, provide for interactive real-time features such as echoing current time, conditional execution based on logical comparisons, querying or updating a database, sending an e-mail etc., with no programming or CGI scripts. (HTTP Server specific)