Web 2.0 has metamorphosed the complete scenario of internet.
In the AJAX world, most of the working functionality is derived by efficient technology methods and ingrained software dependency. In order to scratch deep down the bottom the differential aspect of this technology must be understood. There are a number of truth and lies rotating inside this AJAX world. The basic and most influential changes are mentioned below which clarify the truths prevailing and the lies hidden inside this framework:
- The specific difference between using XHR request and IFRAME request is that the IFRAME processed requests are cached in history of browser which is not possible in XHR.
- The XHR requests are irreversible in nature. It means if a user clicks the forward button on the browser and jumps to the next page, then if he tries to press the backward button on browser, a user will not be taken to the previous page which is controlled by AJAX. Rather, the user is taken to the page before the AJAX code. This case is totally opposite in IFRAME tags.
- AJAX implements the concept of Single Object Refreshing (SOR). It means the object component retrieves information from server, tweaks the DOM without refreshing the whole page. As a result of this, a lot of processing power is used.
- AJAX makes JavaScript an object oriented stature rather than a procedural environment. The class libraries are defined to encapsulate the object behavior. Strings are even treated as object with properties.
- IFRAMES never provide a graceful method for checking the state of requests. IFRAME renders the response sent back from the server. If the response is in HTML the IFRAME must be able to navigate the DOM to retrieve the results.
- Asynchronous requests do not cause the browser to block the request. The browser can use continuously other components of web application. Inherent use of multiple asynchronous requests requires unique IFRAME for a single request. It becomes hard to manage and even raises complexity coz of embedding them in web pages.
- Any browser which does not support AJAX XHR request and if a page is loaded into the browser ,then most of the remoting toolkits have a hidden IFRAME to provide fake XHR support to the page.
- Previously, the IFRAME which is a normal HTML frame is used to trip back data from the server.
Precisely, it is embedded in other HTML page to do work.
Aditya K Sood