AJAX requests Synchronous Vs Asynchronous

Question

Is there any difference in performance ( speed wise ) between a synchronous request and and asynchronous request?

What all are the reasons for using an asynchronous

Answer 1

@Thomas Hansen answer is right but I found a clear explanation with benefits of Asynchronous.

Synchronous is simple, but wait for the server response, thus block the execution of the caller for a period and slower than asynchronous while processing the request.

Asynchronous is required setting, do not wait after submitting the request and immediately return control to the caller, thus faster than Synchronous.

I am coming here when I have to use upload control which has both functionalities in the question and looking the pros and cons of this functionality.

I got the another link which explained with a real example. (the link is the specific tool, so understand the logic)

• The major difference is the response time from our servers. At the time of upload, synchronous will validate file and create the passcode in real-time. Asynchronous will send the file to our server's queue and deliver notification via email once it is processed.

• Synchronous is not ideal for multiple, large CSV file since you will need to wait until the file is processed by the server to submit another request. On large files, this also may cause your browsers to return with timeout errors due to the server being too busy. If you have multiple files, asynchronous will allow you to submit multiple files to the server queue to be processed with a email receipt once completed.

https://www.aspsnippets.com/Articles/Difference-between-Synchronous-Sync-and-Asynchronous-Async-Request-Call-in-AJAX.aspx