Web Apps Using Ajax
The result is that users are unaware that their web application is exchanging information with the database. It feels like their web development project is instantly responding – allowing for simpler user interfaces and easier to use web applications.
Drawbacks to Ajax:
- Added complexity – dynamic updates to user interfaces introduce another level of detail to user interfaces and behavior of web development projects. Examine user interfaces to avoid overusing Ajax techniques.
- If the network has a momentary delay, the application could appear to “hang”. With a non-Ajax application, a user expects to wait after clicking a Submit button. For an Ajax application with no Submit button, there may also have to be an icon that shows background activity, e.g. turning hourglass, if the network is delayed.
- Bookmarks may not work – dynamic changes to web pages may be difficult to mark, unless developers use the URL fragment identifier to track dynamic changes.
- Check the behavior for the “Back” button in the browser – dynamic updates to user interfaces may not be in the history that the Back button uses. Developers typically use invisible IFRAMES (inline frames) to ensure the back button history tracks dynamic changes.
- Browser compatibility – if Ajax is used with Microsoft Internet Explorer v6, then ActiveX must be enabled.
Browsers that support Ajax:
- Mozilla, Mozilla Firefox, Netscape version 7.1 and above, and other Gecko based browsers
- Opera Web Browser version 8.0 and above, including versions of the Opera Mobile Browser version 8.0 and newer
Browsers that do not support Ajax:
- Microsoft Internet Explorer for Windows version 4.0 and below
- Microsoft Internet Explorer for Macintosh, all versions
- Opera 7 and below
- Browsers designed for use by the visually impaired