Please note that as of October 24, 2014, the Nokia Developer Wiki will no longer be accepting user contributions, including new entries, edits and comments, as we begin transitioning to our new home, in the Windows Phone Development Wiki. We plan to move over the majority of the existing entries over the next few weeks. Thanks for all your past and future contributions.
While the request is going to the server, the user can continue using the page for reading or selecting things, so delays are no more a feature of browsing.
Sites created using AJAX offer also the possibility to auto-fill input fields based on predictive text or previous user entries.
AJAX is the future of mobile browsing as you can create rich mobile applications for browsers making a richer experience to the user.
The latest version of Nokia Browser supports AJAX development.
More information on http://en.wikipedia.org/wiki/AJAX