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Lengthy Display Results
A common question in front of Mobile Designers is , "how many items should be displayed on the screen?" For older browsers, the maximum page size limited things closely.But many current browsers are capable of displaying entire desktop web pages on a mobile screen. The point to be considered is, the balance between scrolling for more results and fetching them.
A) Web pages without scripting
The optimal length for the number of items displayed from a longer list depends especially on the time to refresh the list. Limit the list to a maximum of two to three screens of results based on the current distribution of screen sizes. Place controls to navigate to the next screen at the bottom of the list.
A network request introduces a delay.
B) Web pages with scripting
Use scripting (AJAX) to achieve the same user experience as applications, above. Keep both the next and previous set of results in memory, displayable with no delay.
With no delay in fetching the next page, keeping the display limited to just the current screen eliminates the need for scrolling at all. Next and previous controls at the top of the screen allow quick navigation
- There are two relevant costs to the user associated with navigating lists: scrolling through lists, and navigating between pages.
- The Next/Previous method of navigating between pages is well understood amongst Internet users, so the cognitive cost of using it is quite low.
- If the Next button has focus when the screen is drawn (either by it being the first control or by manipulating focus, depending on the platform), then a single keypress will get the user to the next page.
- If there is a fetch delay, then scrolling will have some advantages over many fetches.The list is limited to approximately the size that will avoid the user being lost on a very long page.