According to a study by Zona Research in 1999, 30 percent of visitors leave the website, if it takes more than 8 seconds for a web page to load. Furthermore, this figure increases to 70 percent, if the page does not open up in less than 12 seconds. (AFSCME.org.) In light of this research, it is obvious that web pages that take a long time to load are likely to be abandoned before the content is even visible on the screen. Not only will visitors leave the website, but also they will not come back, because of a slow-loading site. There are websites that are exceptions, of course, such as online game, artistic and musical band sites. Visitors to websites of this nature are often willing to wait longer for the content.
Because the loading speed of webpages is such an important part of usability, designers should make sure that the webpages open up fast, even on a standard dial-up connection. There are some basic guidelines that designers can follow in order to reduce the download time of the pages.
The first guideline to decrease web page loading time is to use animation sparingly. Graphic animations are often redundant and distract visitors away from the actual content of the page. Unless the purpose of the animation is to get people’s attention to that part of the page, it is not recommended to use flashy animation.
KISS (“Keep it simple, stupid”) is a good piece of advice for any website designer. Depending on the nature of the website, the level of simplicity from the user standpoint needs to be determined. For business websites, designers should concentrate on elements that are useful from the user point-of-view, instead of cramming the pages with lots of attractive graphics and complicated interactive elements. Simple designs that use graphics modestly can be very attractive.
A good example of a website design that follows the KISS rule is the homepage of Google. In this case, the simple design is aesthetically beautiful and most importantly, the website is very simple to use and loads very fast.
Many designers use images that include text even if the image could be replaced by regular text content in the HTML-document. Text content in HTML-documents take very little time to load, whereas the file size of images is often quite large and may take several seconds to load.
It is recommended to use the same images throughout the website, whenever possible. The reasoning behind this advice is that when an image is downloaded once, it is saved in the web browser’s cache. When a user navigates on the website, her web browser retrieves the images, which have already been loaded, from the cache folder of the user’s hard drive. This greatly decreases the time it takes to load a web page, especially for users with a slow connection to the Internet.