Mouseover
From Wikipedia, the free encyclopedia
Mouseover is the term used to indicate the text that appears next to your mouse pointer when you hold a computer mouse over any screen object that is an active link, or over some other GUI element or widget that is capable of performing an action, such as an icon or command button. The mouseover is becoming increasingly popular as a way of "jazzing up" navigation menus on a website. It is also a web design term used to describe any effect that appears on a website that occurs when you hold a computer mouse over a hyperlink or linking image.
Most mouseovers do not really serve any crucial functional purpose but simply add to a website's visual appeal. Usability is not necessarily improved by employing mouseovers; in this respect, it is important to take a look at how a particular mouseover was programmed.
JavaScript is very popular for this purpose but has a tendency to create adverse effects in usability; it may lead to technical problems since JavaScript is a client-based, not fully standardized script language. Some computer users have disabled JavaScript in their web browsers, while interpreting software plugins for blind or otherwise vision-impaired viewers are often incapable of following the weblinks denoted in a JavaScript-powered menu bar. If a web designer chooses to use JavaScript for mouseovers anyway, it is imperative to make sure that weblinks still work when JavaScript is disabled.
Some mouseovers are programmed in Java. Again, this is not to be recommended since not every web browser is equipped with a Java plugin; moreover, loading up the Java web console slows down performance especially on older computers. Finally, malignant code can easily be hidden in Java menu applets, and interpreter plugins (see above) have great difficulty in distilling hyperlinks from this kind of menu bar. Usability of Java-based menu bars is therefore very low; Flash-based mouseovers and menu bars, however, are even worse in this respect. While often visually appealing, Flash applets require a proprietary browser plugin; they are not found on every computer, they are sometimes outdated, and some people (and especially companies on their employees' computers) even choose to disable Flash altogether for security reasons. A web site can therefore become immaneuverable for some viewers if no alternate menu bar is supplied. JavaScript is often used to detect whether a browser has a Flash plugin and to supply an alternate menu bar if it doesn't. For those who also have JavaScript disabled, this provides no solution either. Same as most Java applets, Flash mouseovers consist of self-contained compiled code that no interpreter plugin has a way of deciphering.
Since most modern web browsers support CSS technology, a good workaround is to define mouseover styles for links in a style sheet. Aside from the style sheet's contents, CSS mouseovers are simply defined by a class attribute in a hyperlink's anchor tag which can be understood both by interpreting plugins for vision-impaired viewers and a web browser with disabled JavaScript or with no Flash and Java plugins. Even if CSS is not (fully) implemented in a viewer's browser, hyperlinks will still work.
All in all, it is important to keep in mind that as with many things, form should always follow function and mouseovers should be means to an end. They should enhance a viewer's experience while browsing a website, and not hamper or make it less enjoyable in any way.
