According to Microsoft: "Microsoft JScript is a powerful scripting language targeted specifically for the Internet.
It is implemented as a fast, portable, lightweight interpreter for use in World Wide Web browsers and other applications
that use Microsoft ActiveX Controls, Automation servers, and Java applets. ...
JScript is the Microsoft implementation of the ECMA 262 language specification.
It is a full implementation, plus some enhancements that take advantage of capabilities of Microsoft Internet Explorer.
JScript is not a cut-down version of any other language (it is only distantly and indirectly related to Java, for example),
and it is not a simplification of anything. It is, however, limited.
You cannot write standalone applications in it, for example, and it has little capability for reading or writing files.
Moreover, JScript scripts can run only in the presence of an interpreter, either in a Web server or a Web browser.
What is Dynamic HTML? ... Dynamic HTML provides a comprehensive object model for HTML.
This model exposes all page elements as objects.
These objects can easily be manipulated, by changing their attributes or applying methods to them at any time.
Dynamic HTML also provides full support for keyboard and mouse events on all page elements.
Support for the Document Object Model enables dynamic content, style, and positioning effects as well as data binding and scriptlets.
The Document Object Model (DOM) is a platform- and language-neutral interface
that permits script to access and update the content, structure, and style of a document.
The DOM includes a model for how a standard set of objects representing HTML and XML documents are combined,
and an interface for accessing and manipulating them.
Web authors can use the DOM interface in Microsoft Internet Explorer 5 and later to take advantage of this dynamic model."