AJAX allows exchanging of data with a server. It is possible to update
only parts of a web page and avoid reloading of the whole page.
Usually data are received asynchronously. While waiting for the external answer
the web page stays reactive and can execute other scripts. Finally the asynchronous
answer is processed within a callback function given at the preceding request call
to the server. Internally a XMLHttpRequestObject is used for asynchronous data requests, but
those details are hidden behind the simple jQuery AJAX methods.
Example for dynamically supplied external contents:
AJAX allows more reactive web pages
If you enter any character in the following input field you will receive
an immediate response from the server giving you
a hint if there are matching entries within the server data base.
(Words starting with one of the letters 'a', 'b', 'd' or 'e' will have multiple alternatives within data base.)