26-12-2012, 03:42 PM
Ajax
Ajax.ppt (Size: 561 KB / Downloads: 34)
What is AJAX ?
Asynchronous Javascript and XML.
Not a stand-alone language or technology.
It is a technique that combines a set of known technologies in order to create faster and more user friendly web pages.
It is a client side technology.
Purpose of AJAX
Prevents unnecessary reloading of a page.
When we submit a form, although most of the page remains the same, whole page is reloaded from the server.
This causes very long waiting times and waste of bandwidth.
loading only the necessary information, and making only the necessary changes on the current page without reloading the whole page.
Which brings us to Ajax
Ajax is a pattern for building applications on the browser.
The pattern is:
Use JavaScript to control the show.Use it to asynchronouslyrequest and retrieve data fromremote servers, whenever the program thinks this is a good idea (i.e. not just when the user does something),
Use XML to send numerical or text-style data to the browser. Then use JavaScript to extract data from the XML,
Use HTML and CSS for display: manipulate this using JavaScript.
Pros/Cons
Advantages:
Independent of server technology.
Apart from obtaining the XMLHTTP object, all processing is same for all browser types, because Javascript is used.
Permits the development of faster and more interactive web applications.
Disadvantages:
The back button problem. People think that when they press back button, they will return to the last change they made, but in AJAX this doesn not hold.
Possible network latency problems. People should be given feedback about the processing.
Does not run on all browsers.
Ajax.ppt (Size: 561 KB / Downloads: 34)
What is AJAX ?
Asynchronous Javascript and XML.
Not a stand-alone language or technology.
It is a technique that combines a set of known technologies in order to create faster and more user friendly web pages.
It is a client side technology.
Purpose of AJAX
Prevents unnecessary reloading of a page.
When we submit a form, although most of the page remains the same, whole page is reloaded from the server.
This causes very long waiting times and waste of bandwidth.
loading only the necessary information, and making only the necessary changes on the current page without reloading the whole page.
Which brings us to Ajax
Ajax is a pattern for building applications on the browser.
The pattern is:
Use JavaScript to control the show.Use it to asynchronouslyrequest and retrieve data fromremote servers, whenever the program thinks this is a good idea (i.e. not just when the user does something),
Use XML to send numerical or text-style data to the browser. Then use JavaScript to extract data from the XML,
Use HTML and CSS for display: manipulate this using JavaScript.
Pros/Cons
Advantages:
Independent of server technology.
Apart from obtaining the XMLHTTP object, all processing is same for all browser types, because Javascript is used.
Permits the development of faster and more interactive web applications.
Disadvantages:
The back button problem. People think that when they press back button, they will return to the last change they made, but in AJAX this doesn not hold.
Possible network latency problems. People should be given feedback about the processing.
Does not run on all browsers.