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JavaScript 2.0-The Complete Reference, Second ... - freecodingtutorial

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Table 21-7: Some Proprietary Features Introduced in Internet Explorer 4<br />

Feature Description<br />

document.all and access to the style object of an element is the<br />

main way IE DHTML is implemented.<br />

window.external Allows scripts to access extended object model features provided<br />

by the client (e.g., a Browser Helper Object). For more information,<br />

see the MSDN.<br />

IE Event model Internet Explorer's proprietary event model (event bubbling) as well<br />

as proprietary event handlers.<br />

CSS Filters Offers a variety of nonstandard special effects for fonts and page<br />

transitions.<br />

Data Binding Permits HTML elements to be bound to external data sources in<br />

order to automate retrieval and update of information without<br />

requiring explicit action such as form submission.<br />

Scriptlets Encapsulated <strong>JavaScript</strong> that can be included in documents as an<br />

embedded object.<br />

Modal Windows <strong>The</strong> showModalDialog() and showModelessDialog() methods of<br />

Window permit the creation of special kinds of pop-up windows.<br />

One of the more interesting features available as of IE4 is the ability to use scriptlets. Scriptlets<br />

are HTML documents embedded in the page with an tag. <strong>The</strong>ir purpose is to<br />

provide reusable functional units—for example, DHTML rollover effects or animation. <strong>The</strong> idea<br />

is to facilitate script reusability by encapsulating commonly used functionality in these<br />

components. Although scriptlet technology is interesting and often useful, it has been<br />

superseded in Internet Explorer 5 and later by a related technology, DHTML Behaviors, so we<br />

mention it only for historical perspective.<br />

One lesser-known capability of IE4+ is the ability to disable instance properties for document<br />

objects. By setting the expando property of the Document object to false, any attempt to set<br />

instance properties in the document object hierarchy will throw an error.<br />

Internet Explorer 5<br />

Internet Explorer 5 provides even more features that make Web pages act more like<br />

applications than documents. A brief outline of some of these powerful features is found in<br />

Table 21-8.<br />

Table 21-8: Some Proprietary Features Introduced in Internet Explorer 5<br />

Feature Description<br />

HTML+TIME <strong>The</strong> Timed Interactive Multimedia Extensions (TIME) is an XMLdefined<br />

language providing synchronization of sound, video, and<br />

other effects in the page.<br />

Dynamic<br />

Properties<br />

Permits the assignment of an expression (rather than a static<br />

value) as the value of a property. <strong>The</strong>se expressions are<br />

dynamically evaluated to reflect the current state of the page.<br />

HTML Applications HTML Applications (HTAs) are HTML pages (and associated<br />

scripts) run on the client as fully trusted applications. <strong>The</strong>y are<br />

useful for writing code for Internet Explorer that is not subject to<br />

the usual security restrictions associated with untrusted code.<br />

Attached DHTML A powerful technology that allows code performing some

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