Q 2 -
What is advantage of Ajax
Basic advantage of Ajax is Bandwidth utilization means when we have more type of data on same page or use more included page , hence data is fetched without loading the page it's save memory also it is more interactive no any user want lose their information from that page , so the concentrate only on same page fastest where loading a page is difficult or more time consuming Ajax do best work So why in all modern website need concentration to use Ajax ,it is a Browser technology independent of web server software .
Like every thing advantage and disadvantage Ajax has too some disadvantage like
When we use Ajax it is difficult to return back page , when we click on back button we
Got first page(because same page is using for sending or fetching data but when we need just last use thing we could not able to seen last modified data they gone to starting point
And also need to more concentration because it is faster to implement but still it is very beneficial to us