Browser Navigation Features
When designing a navigation system, it is important to consider the environment the system will exist in. On the Web, people use web browsers such as Netscape Navigator and Microsoft Internet Explorer to move around and view web sites. These browsers sport many built-in navigation features.
Open URL allows direct access to any page on a web site. Back and Forward provide a bidirectional backtracking capability. The History menu allows random access to pages visited during the current session, and Bookmark enables users to save the location of specific pages for future reference. Web browsers also go beyond the Back button to support a "bread crumbs" feature by color-coding hypertext links. By default, unvisited hypertext links are one color and visited hypertext links are another. This feature helps users understand where they have and haven't been and can help them to retrace their steps through a web site.
Finally, web browsers allow for a prospective view that can influence how users navigate. As the user passes the cursor over a hypertext link, the destination URL appears at the bottom of the browser window, ideally hinting about the nature of that content (see Figure 4.1). If files and directories have been carefully labeled, prospective view gives the user context within the content hierarchy. If the hypertext link leads to another web site on another server, prospective view provides the user with basic information about this off-site destination.
Figure 4.1. In this example, the cursor is positioned over the Investor Info button. The prospective view window at the bottom shows the URL of the Investor Info page.
Much research, analysis, and testing has been invested in the design of these browser-based navigation features. However, it is remarkable how frequently site designers unwittingly override or corrupt these navigation features. For example, designers often modify the unvisited and visited link colors with no consideration for the bread crumbs feature. They focus on aesthetics, attempting to match link colors with logo colors. It's common to see a complete reversal of the blue and purple standard. This is a classic sacrifice of usability3 for aesthetics and belies a lack of consideration for the user and the environment. It's like putting up a green stop sign at a road intersection because it matches the color of a nearby building.
Given proper understanding of the aesthetic and usability issues, you can in fact modify the link colors and create an intelligent balance.4 Unfortunately, this convention has been violated so frequently, the standard may no longer be standard.
A second common example of inadvertently disabling valuable browser navigation features involves prospective view. Image maps have become a ubiquitous navigation feature on web sites. The graphic navigation bar allows the aesthetically pleasing presentation of navigation options. Unfortunately, server-side image maps completely disable the prospective view feature of web browsers. Instead of the destination URL preview, the XY coordinates of the image map are presented. This information is distracting, not useful. Again, a solution that balances aesthetics and usability is available. Through an elegant use of tables (or by using client-side image maps), you can present a graphical navigation bar that leverages the browser-based prospective view feature.
Once you are sensitive to the built-in navigation features of web browsers, it is easy to avoid disabling or duplicating those features. In fact, it is both possible and desirable to find ways to leverage them. In designing navigation systems, you should consider all elements of that system. Web browsers are an extremely common and integral part of the user's navigation experience. From a philosophical perspective, we might say that web pages do not exist in the absence of a web browser. So, don't override or corrupt the browser!