AJAX :

it’s shorthand to ” Asynchronous JavaScript and XML ”

Historical Background :

in the early web stages , websites where all HTML based so any small change in the content of the web page needs the webpage to be all reloaded , this SUCKS  and adds loads to the bandwidth and the server , after Java applets are introduced , an asynchronous data reloading was available also Microsoft introduced in internet explorer 5 the  XMLHTTP control  then later on google deployed the AJAX when it used it in GMAIL and GOOGLE maps

check this out when Ajax what introduced to the public Ajax: A New Approach to Web Applications

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AJAX Main achievements :

the transfer of data between servers and browsers became asynchronous no need to reload the page for each single change in the page ; you can find something like  suggested links in search Engines  , Google and Bing instance ,

however XML is not the only used for data interfered  often JSON or although other formats such as preformatted HTML or plain text can also be used.instead .

some Drawbacks :

  • clicked links are not saved into the browser history also it’s difficult to bookmark certain page at a certain position , because the pages changes without changing the URL of the main page so if you are building an Ajax gallery for example you can’t bookmark a single page , or go back or forward but alot of developers are Creating techniques to over come this , as by using the Hash Object

 

Ajax frameworks:

Ajax Frame works are  frame works Built to help users to Develop ajax applications Easily AJAX has different Frame works in different languages

  • Javascript AJAX  frameworks : like Jquery , MooTools , dojo toolkit , ASP.net AJAX
  • JAVA Frameworks for server side AJAX :  Google webkit , BackBase , Apache webkit
  • C++ : wt  webkit
  • ASP.NET AJAX : Microsoft Atlas formerly
  • Pyjamas , a widget library with a Python to JavaScript compiler