Monday, November 10, 2008

Merits of using JavaScript

Less server interaction: You can validate user input before sending the page off to the server. This saves server traffic, which means saving money. • Immediate feedback to the visitors: They don’t have to wait for a page reload to see if they have forgotten to enter something. • Automated fixing of minor errors: For example, if you have a database system that expects a date in the format dd-mm-yyyy and the visitor enters it in the form dd/mm/yyyy, a clever JavaScript script could change this minor mistake prior to sending the form to the server. If that was the only mistake the visitor made, you can save her an error message—thus making it less frustrating to use the site. • Increased usability by allowing visitors to change and interact with the user interface without reloading the page: For example, by collapsing and expanding sections of the page or offering extra options for visitors with JavaScript. A classic example of this would be select boxes that allow immediate filtering, such as only showing the available destinations for a certain airport, without making you reload the page and wait for the result. • Increased interactivity: You can create interfaces that react when the user hovers over them with a mouse or activates them via the keyboard. This is partly possible with CSS and HTML as well, but JavaScript offers you a lot wider—and more widely supported—range of options. • Richer interfaces: If your users allow for it, you can use JavaScript to include such items as drag-and-drop components and sliders—something that originally was only possible in thick client applications your users had to install, such as Java applets or browser plug-ins like Flash. • Lightweight environment: Instead of downloading a large file like a Java applet or a Flash movie, scripts are small in file size and get cached (held in memory) once they have been loaded. JavaScript also uses the browser controls for functionality rather than its own user interfaces like Flash or Java applets do. This makes it easier for users, as they already know these controls and how to use them. Modern Flash and Macromedia Flex applications do have the option to stream media and—being vector based—are visually scalable, something JavaScript and HTML controls aren’t. On the other hand, they require the plug-in to be installed.