Bandwidth usage
By generating the HTML locally within the browser, and only bringing down JavaScript calls and the actual data, Ajax web pages can appear to load relatively quickly since the payload coming down is much smaller in size. An example of this technique is a large result set where multiple pages of data exist. With Ajax, the HTML of the page (e.g., a table structure with related TD and TR tags) can be produced locally in the browser and not brought down with the first page of the document.
In addition to “load on demand” of contents, some web-based applications load stubs of event handlers and then load the functions on the fly. This technique significantly cuts down the bandwidth consumption for web applications that have complex logic and functionality.
Separation of data, format, style, and function
A less specific benefit of the Ajax approach is that it tends to encourage programmers to clearly separate the methods and formats used for the different aspects of information delivery via the web. Although Ajax can appear to be a jumble of languages and techniques, and programmers are free to adopt and adapt whatever works for them, they are generally propelled by the development motive itself to adopt separation among the following:
- Raw data or content to be delivered, which is normally embedded in XML and sometimes derived from a server-side database.
- Format or structure of the webpage, which is almost always built in HTML or XHTML and is then reflected and made available to dynamic manipulation in the DOM.
- Style elements of the webpage: everything from fonts to picture placement are derived by reference to embedded or referenced CSS.
- Functionality of the webpage, which is provided by a combination of:
- Javascript on the client browser (also called DHTML),
- Standard HTTP and XMLHttp or client-to-server communication, and
- Server-side scripting and/or programs using any suitable language preferred by the programmer to receive the client’s specific requests and respond appropriately.
Licensed under the GNU Free Documentation License. It uses materials from the Wikipedia.
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