The perception of the visual complexity of World Wide Web (Web) pages is a topic of significant interest. Previous work has examined the relationship between complexity and various aspects of presentation, including font styles, colours and images, but automatically quantifying this dimension of a web page at the level of the document remains a challenge. In this paper we demonstrate that areas of high complexity can be identified by detecting areas, or ‘chunks’, of a web page high in block-level elements. We report a computational algorithm that captures this metric and places web pages in a sequence that shows an 86% correlation with the sequences generated through user judgements of complexity. The work shows that structural aspects of a web page influence how complex a user perceives it to be, and presents a straightforward means of determining complexity through examining the DOM.

The visual complexity of Web pages is much talked about; “complex Web pages are difficult to use,” but often regarded as a subjective decision by the user. This subjective decision is of limited use if we wish to understand the importance of visual complexity, what it means, and how it can be used. We theorize that by understanding a user's visual perception of Web page complexity, we can understand the cognitive effort required for interaction with that page. This is important because by using an easily identifiable measure, such as visual complexity, as an implicit marker of cognitive load, we can design Web pages which are easier to interact with. We have devised an initial empirical experiment, using card sorting and triadic elicitation, to test our theories and assumptions, and have built an initial baseline sequence of 20 Web pages along with a library of qualitative and anecdotal feedback. Using this library, we define visual complexity, ergo perceived interaction complexity, and by taking these pages as “prototypes” and ranking them into a sequence of complexity, we are able to group them into: simple, neutral, and complex. This means we can now work toward a definition of visual complexity as an implicit measure of cognitive load.

The rapid advancement of World Wide Web (Web) technology and constant need for attractive Websites produce pages that hinder visually impaired users. We assert that understanding how sighted users browse Web pages can provide important information that will enhance Web Accessibility, especially for visually impaired users. We present an eye tracking study where sighted users' browsing behaviour on nine Web pages was investigated to determine how the page's visual clutter is related to sighted users' browsing patterns. The results show that salient elements attract users' attention first, users spend more time on the main content of the page and users tend to fixate on the first three or four items on the menu lists. Common gaze patterns begin at the salient elements of the page, move to the main content, header, right column and left column of the page and finish at the footer area. We argue that the results should be used as the initial step for proposing guidelines that assist in designing and transforming Web pages for an easier and faster access for visually impaired users.