Introduction to Dynamic HTML: The Old Standard about Standards
August 24, 1998
Dynamic HTML was and still is a logical and wonderful idea whose time
has come. Netscape thought so. Microsoft
thought so. Yet, they didn't think alike. Netscape introduced a very
modest vision of DHTML, debuted in Navigator
4.0. By and large, Netscape's DHTML was limited to the concept of
"layers," also known as Cascading Style
Sheet Positioning, a crucial concept which we will look at more
closely in a short while. Microsoft, on the other
hand, chose to shoot for the moon, providing developers
with surprisingly complex DHTML support in Internet Explorer
4.0, wherein many objects on the page were manipulable,
including support for CSS Positioning.
In the past year, quite a lot of Web development time has been
spent haranguing over the challenge of coding pages
which function under both versions of DHTML. Known as
cross browser DHTML,
a cottage industry has sprung
up to span the ravine between browsers. The development community
has its collected fingers crossed, however, that
soon a common standard will emerge, allowing developers to focus
on the true subject at hand, rather than compatibility
issues.
Much of what we term "Dynamic HTML" -- the set of page
elements which are manipulable -- is defined by
a construct called the
Document Object Model
(or "DOM").
This model describes each page element and which
of its characteristics may be modified, and how so. As you can
imagine, Netscape and Microsoft do not share a common
DOM. The hopes of DHTML standardization rest strongly on the
success of a standardized DOM, currently in development
by the World Wide Web Consortium (W3C) --
http://www.w3c.org/DOM/.
Curriculum
DHTML, to stress the point, is not a language itself. In practice,
one programs Dynamic HTML effects using a
combination of
HTML,
Cascading Style Sheets, and
JavaScript. The
Document Object Model, described earlier, provides
a programming interface between HTML/CSS and JavaScript.
In this introductory article we will explore three main components
of Dynamic HTML authoring:
1. Positioning; precisely placing blocks of content on the page and,
if desired, moving these blocks around.
2. Style modifications; on-the-fly altering the aesthetics of content
on the page.
3. Event handling; how to relate user events to changes in positioning
or other style modifications.
Technically speaking, DHTML positioning is actually a subset of
style modifications; however, this introduction
will be all the clearer if we address positioning as its own topic.
Introduction to Dynamic HTML
Introduction to Dynamic HTML
Introduction to Dynamic HTML: Dynamic Positioning
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