Ajax is an acronym for Asynchronous Javascript and XML. It is used to communicate with the server without refreshing the web page and thus increasing the user experience and better performance.There are two types of requests synchronous as well as asynchronous. Synchronous requests are the one which follows sequentially i.e if one process is going on and in the same time another process wants to be executed, it will not be allowed that means the only one process at a time will be executed. This is not good because in this type most of the time CPU remains idle such as during I/O operation in the process which are the order of magnitude slower than the CPU processing the instructions. Thus to make the full utilization of the CPU and other resources use asynchronous calls.the word javascript is present here. Actually, the requests are made through the use of javascript functions. Now the term XML which is used to create XMLHttpRequest object.
Thus the summary of the above explanation is that Ajax allows web pages to be updated asynchronously by exchanging small amounts of data with the server behind the scenes.
For implementing Ajax, only be aware of XMLHttpRequest object. Now, what actually it is. It is an object used to exchange data with the server behind the scenes. Try to remember the paradigm of OOP which says that object communicates through calling methods (or in general sense message passing). The same case applied here as well. Usually, create this object and use it to call the methods which result in effective communication. All modern browsers support the XMLHttpRequest object.
