Frames have the potential to confuse users by breaking the user's model of a website. For instance, instead of the concept of a node as being a single unit of information, framed pages may consist of many units that can go in any direction, which may make it difficult to later go back to the original node. Also, viewers cannot bookmark frames, frames are not accessible to many users who employ assisting technology such as screen readers, and some search engines reject the framed pages outright, so what is left is only the main or dominant frame (However, there are some ways around this, see http://searchenginewatch.com/ webmasters/frames.html); And, of course, users hate poorly designed, framed web pages (Nielsen, 1996).
Proper and parsimonious use of frames may, however, be appropriate for websites if it promotes easier navigation. (see Priestley, 1997, for a more detailed discussion of this). One way to use frames is by using a navigational menu frame (also called an inline frame, which is a frame dedicated to displaying the main navigational links within a site). A menu frame can solve the problem of the disappearing menu when users scroll down a non-framed page because the menu frame will always be visible (these are normally placed on the left side or top of the screen). Drawbacks of using menu frames is that the amount of information placed in the menu page must be rather small in order for the entire menu to fit within the frame. That is, forcing the user to scroll to see the entire menu frame defeats the purpose of having one -which is to always have a visible menu.
Frames might also be used to allow users to follow an external link while keeping the original, initial site in view. To do this, typically the top frame shows the initial site as a reminder to return to that site and the lower frame shows the sites that are external to the initial site (hotmail.com uses this technique). However, there should be an option to completely leave the initial site. In addition, links that exit the site should use the TARGET="_top" tag to ensure that users can leave the initial site without being embedded within the frameset of the initial site.
In a study we examined performance and preference of framed versus non-framed pages in which participants were presented with four documents, each with a different link arrangement. For each arrangement they were instructed to search for specific information pertaining to ten questions related to that document (such as, "Who found evidence linking tribes from Siberia to the Americas?"). In one condition the links were embedded within a document, as would be found with many online documents (see Figure 1). This was accomplished by using an original online article with embedded links. A second condition placed links at the upper-left of the document (see Figure 2). Another condition placed links within a horizontal, top frame above the document (see Figure 3) and a fourth condition placed the links within a vertical frame at the left of the document (see Figure 4).
An analysis of the results revealed no significant differences in search performance (accuracy, search time, and search efficiency) or preference between the four conditions. Interestingly, the participants had rather strong preferences towards the top-left and horizontal framed layouts --which, in effect, canceled each other out.
In a follow-up study (Bernard & Hull, 2002) that only compared the top-left with the vertical frame conditions in terms of preference did reveal significant differences that favored the frame condition [z = -3.58, p < .001]. Examining the number of participantsí ranking either the Frame or Top-Left (no fame) conditions as their first choice further illustrates the preference for the Frame condition (see Figure below).
Usability Research Lab