Cross Browser Compatibility
There are literally hundreds of web browsers in use around the
world. All of them implement the W3C document standards a little
differently. Web designers must wrestle with these differences
to make a web site work. This article discusses the...
Designing Professional Web Pages
If your Web site doesn't project a professional and polished image to your visitors, your credibility and that of your products and services will suffer. Image is everything--especially online where your competitor is only one mouse click away! ...
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...
Showing and Hiding HTML elements using Layers
A long time back I visited a site that had a very fancy, animated navigation bar. Now, as a professional web developer, I'm not in favor of DHTML-supported, fancy navigation bars, but it was very fascinating. What they had done was, whenever you...
What Could Be Worse Than Your Viewers Not Seeing Your Site Display Properly?
What if they never get to your site to see it?
If you want your site listed on search engines then make sure that you have correct HTML code. Many search engines cannot properly catalog or index a site that has HTML errors. This can greatly...
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
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)
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.