|
|
|
Finding a Good HTML Editor
Once you've decided to write your own HTML, and you've got some
idea of how it all works, there's one thing left to think about:
which program are you going to use to do it? While you can use
programs like Notepad or Wordpad that come with...
How I Slashed The Load Time For My Website By 200-300%...And So Can You, For Yours!
Here is my latest article. It may be freely used in ezines, on websites or in e-books, as long as the Resource Box is left intact. I would appreciate notification of where it was used, and if possible, a copy of the ezine or newsletter that it was...
HTML Editors 101 - Smaller Is Better
Microsoft FrontPage and Macromedia's Dreamweaver aren't the only HTML editors on the market. In fact, niche HTML editors from various independent developer offer a number of advantages over the big boys. SiteSpinner SiteSpinner is a user-friendly...
Web Design for the No-Talent Artist
Not everyone can hit a 90 mile per hour fast ball 400 feet. That's why there are so few major league baseball players. Most everyone enjoyed art class while in school, but we also realized there was probably only one in each classroom who actually...
Website Colors
In 1994, Netscape defined 216 colors that have priority in
browsers based on the 256 colors displayed by an 8-bit system.
40 colors display differently between PCs and MACs and are
therefore eliminated.
These 216 fixed colors, known as web...
|
|
| |
|
|
|
|
|
|
DHTML-Introduction
Think of DHTML as not a singular technology but a combination of three
existing technologies glued together by the Document Object Model (DOM):
1. HTML - For creating text and image links and other page elements.
2. CSS - Style Sheets for further formatting of text and html plus other
added features such as positioning and layering content.
3. JavaScript - The programming language that allows you to accesses and
dynamically control the individual properties of both HTML and Style Sheets.
The way JavaScript accesses the properties of an HTML document is through
the Document Object Model (DOM). The job of the DOM is to expose all the
attributes of HTML and Style sheets to JavaScript control. All you need to
know about the DOM is what JavaScript commands it accepts. Not that easy,
as different browsers have their slightly different versions of the DOM, so
they access HTML properties differently as well as display them differently.
So how do you locate an HTML element on a page and change its property?
This is the job of JavaScript. Obviously, I cant into all the details of
JavaScript or the DOM, but here is an example of how JavaScript can change a
visibility of a style sheet layer in both browsers.
Note: That every piece of HTML has a location much like a directory in a
phone book. When finding that piece of HTML you have to go through the same
hierarchy process of searching for a name in the phone book such as
(state) Washington -> (City) Seattle -> (Listings) j -> (Name) Jessica
In JavaScript, a reference to this would be equivalent to
washington.seattle.j.jessica
Now Jessica may have additional information such as her address and phone
number, so the JavaScript reference would be written this way.
washington.seattle.j.jessica.address
or
washington.seattle.j.jessica.phone
Lets transcribe the above metaphor to a DHTML document that contains a
layer [myLayer] with style attributes
[top,left,width,height,z-index,visibility,etc] and the layer contains a bit
of text "myText" (Note that the visibility attribute is set to hidden)
100px; height: 100px; z-index: 3; visibility: hidden;">
myText
In Netscape the address to the DIV layer "myLayer" is
document.myLayer
in Explorer it is
document.all.myLayer.style
The W3C way of identifying the address is
document.GetElementById(‘myLayer’).style
To access the properties such as visibility under "myLayer" you would use
these addresses.
Netscape
document.myLayer.visibility
Explorer
document.all.myLayer.style.visibility
W3C
document.getElementById(‘myLayer’).style.visibility
To change the visibility of this layer you would assign a value to your
JavaScript address.
Netscape
document.myLayer.visibility = "visible";
Explorer
document.all.myLayer.style.visibility = "visible";
W3C
document.getElementById(‘myLayer’).style.visibility=”visible”;
Now the previously hidden layer is now visible. This is essentially how
DHTML works, but understand there are hundreds and hundreds of attribute
properties for text, images, documents and windows. Not all these
properties are supported in both browser and sometime accessing a property
requires a few more hurdles, but if you stick to the common denominator
properties both browser use then life it a bit easier. I recommend the
excellent DHTML reference book Dynamic HTML - The Definitive Guide by Danny
Goodman (O'Riley Books) It lists all of the DHMTL properties and their
cross browser compatibilities.
About the Author
Eddie Traversa
DHTML Nirvana http://nirvana.media3.net/ is a site
dedicated to exploring the possibilites of DHTML. It hosts free graphics,
dhtml templates and tutorials. Some of the tutorials emphasis is on
Flash/DHTML integration.
|
|
|
|
|
|
