| Since their almost simultaneous release in the late 1990's, both Adobe Flash (formerly Macromedia Flash) and DHTML have seemed to be at odds, vying for Web designers' attention, as a way to add interactivity to Web sites. Although DHTML adds interactivity to Web pages by using HTML, CSS, the DOM and JavaScript, Flash is a file format that can be integrated into and can interact with HTML pages but is itself a separate technology that is also delivered through Web browsers (see the sidebar "The History of Flash"). The History of Flash Macromedia acquired the vector animation program FutureSplash Animator in 1997. It added interactive and scripting capabilities, renamed the program Flash, and positioned it as a way to create dynamic graphic content for the Web. Up until then, graphics on the Web had been fairly lifeless; animated GIFs were the only substantial way to add motion to the browser window. Flash changed all that by letting Web designers control the appearance and behavior of Web content. Adobe bought Macromedia in 2005 and thus acquired Flash. Although it is clear that Adobe plans to continue the development of Flash, it is still unclear how this will change the nature of the program. It's important to remember that Flash is both a program (from Adobe) and a file format (which has the extension .swf, pronounced swif). When discussing "Flash" you may often find that you need to qualify whether you are talking about using the software or viewing its output. |
The rest of this book deals with how, where, and why you should use DHTML, but it's also important to understand the strengths and weaknesses of DHTML's chief dynamic competition so that you can better decide which technology to use. Flash Advantages Flash has scored points with developers for several reasons, not the least of which is its consistency. Consistent. A Flash file will run more or less the same on a Mac using Internet Explorer 5.5 as it does on a Windows machine running Safari 2.1. Unlike HTML, JavaScript, and CSS, which are interpreted variously by the companies that make Web browsers, a single company develops Flash. Although there are a few diffences in how Flash is integrated with browsers, and occasionally there will be some bugs in beta or earlier releases, in general you only have to create a single Flash file for universal viewing. Ubiquitous. According to Macromedia, 95 percent of the Web-browsing public has some version of the Flash plug-in installed. Although this figure may be a tad optimistic, there is a good chance that the audience for your Web site will be able to view Flash content that you include in your Web site. Attractive. Flash gives designers a wide range of creative tools from which to choose. In addition, Flash Web sites win most of the design awards these days. Small. If they're created right, Flash files deliver a lot of dynamic bang for the buck.
Flash Disadvantages Things look good for Flash so far, but there is another side to the story: Difficult to learn and create. HTML, CSS, and JavaScript can be created with a basic text editor. But to create Flash files, you must purchase and learn to use Adobe Flash, which has a difficult learning curve. Search Engine Optimization. Although the exact alchemy used by search engines such as Google and Yahoo! to index the Web remains a mystery, we do know that they rely on the ability to find plain text. Obviously, since Flash code is not open for viewing, the text in a Flash file cannot be searched. Although there are methods to alleviate this, generally Flash pages will not appear as highly in search results. Plug-in phobia. Although the vast majority of users may have the Flash plug-in, they may not have the most current version; thus, they may not be able to run your cutting-edge Flash movie. To view your site, users may have to download the latest version. You could make a similar argument about browsers, but Web surfers traditionally resist downloading plug-ins. In addition, recent legal maneuvers by Eolas (a company that claims to have patented browser plug-ins) has cast doubt on the future of plug-in-based technology in Web browsers. Though this issue is far from settled, it may have a chilling effect on all plug-in technologies, including Flash. Usability abuses. Flash allows greater versatility with the interface design than straight HTML. But with great power comes great responsibility. Designers are more likely to flaunt standard Web interface conventions in Flash designs and this can lead to confusion for the user. See the sidebar "The Great Usability Debate" for more details. Bloated downloads. Although Flash movies can be very small, making them small takes skill and practice. Many enthusiastic designers forget that the people viewing their sites may have slow Internet connections, so downloading these large files can take a long time.
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