Advantages of AJAX obvious: increased interactivity and dynamic web pages by reducing the amount of information that is loaded, reducing the load on the server, which is also very important, given the continuing growth of information flows in the network “Internet”. In addition, AJAX provides improved functionality of the site.
The most striking and famous examples of AJAX can be called Google Maps. Generally, the use of AJAX on Google confirmed its effectiveness. Actively using AJAX in various forums, chats, social networks.
What is the mechanism of AJAX? A request to a server generated page you will see the user. Queries the user will turn to AJAX-module, which provides work to the server via dynamic address. Information from the database is stored in XML-file, which is formed dynamically and displays information on the site. AJAX provides asynchronous communication. This means that events do not occur immediately after an action, and can take plenty of time before you get the answer. Some queries can be answered at all and not get.
The main disadvantages of AJAX include security (ability to read source code in the browser), the inability to check the browser history pages visit (not work button “Back”), the problem of indexing by search engines (dynamically loaded content is not available for bots). Therefore it is expedient to use AJAX for some of the content of your site.