Now that you've considered all the ways to build links, it's a good time to consider what can go wrong. Links on a site can break when you rename or move files or folders. Links to other Web sites are particularly fragilethey can break at any time, without warning. You won't know that anything's gone wrong until you click the link and get a "page not found" error message.
Broken links are so common that Web developers have coined a term to describe how Web sites gradually lose their linking abilities : link rot . Sadly, you can upload a perfectly working Web site today, and return a few months later to find that many of its external links have died off. They point to Web sites that no longer exist, have moved, or were rearranged.
Link rot is an insidious problem because it violates the confidence of your Web visitors . They see a page that promises to lead them to other interesting resources, but when they click one of the links to try and complete the deal, they're disappointed. Experienced Web surfers won't stay long at a Web site that's suffering from an advanced case of link rotthey'll assume that the site is updated infrequently and move on to a snazzier site somewhere else.
So how can you reduce the problem of broken links? First, you should rigorously test all your internal linksthe ones that point to pages within your own site. Check for minor errors that can stop a link from working, and travel every path at least once. Leading HTML editors include built-in tools that can help automate this drudgery.
External links pose a different challenge. You can't create iron-clad external links, because link destinations are beyond your control and can change at any time. You could reduce the number of external links you include in your Web site to minimize the problem, but this isn't a very satisfying solution. Part of the beauty of the Web is the way a single click can take you from a comprehensive rock discography to a memorabilia site with hand- painted Elvis office supplies . As long as you want to connect your Web site to the rest of the world, you'll need to include external links. A better solution is to test your Web site regularly with a link validator that will walk through every page and check each link to make sure it still leads somewhere.
In the following sections, you'll take a quick look at Web site management and link validators.
Nvu, Dreamweaver, FrontPage, and many other HTML editors include site management tools that let you see your entire Web site at a glance. In most cases, you need to specifically define a Web site in order to take advantage of these features (a process described on Section 4.2.4). Once you've defined the Web site, you get a bird's eye view of everything it holds (see Figure 8-7).
In many ways, looking at the contents of your Web site folders isn't as interesting as studying the Web of links that binds your pages together. Many Web page editors give you the ability to get an at-a-glance look at where all your links lead (see Figure 8-8).