Progress Bar helps to display the file upload status in real-time. The progress bar is very useful to make the file upload process user-friendly. Use xhr option in the $.ajax() method to get the file upload progress and make a progress bar with percentage using JavaScript.

The setTimeout() method executes a function after some specified number of milliseconds. This function is ideal to make an Ajax call after a delay of few seconds. Use window setTimeout() method, you can set a delay in Ajax call for a specific time.

In jQuery Ajax, you can post the data separately. But when you needs to send the entire form data, it is very difficult to get all the form data individually and put together in data settings of Ajax. The jQuery .serialize() method makes this process easier.