Sometimes we need to check username availability instantly before a user presses the submit button after filling a long-sized signup form. In this case we can use AJAX with any technologies like PHP, Codeigniter, Servlet, Struts, JSF, Spring etc. for checking whether the input username is avaialable or already occupied by someone else. So if we give instant result to the user for username availability then sometimes it makes more sensible than while pressing the submit button and goes top of the signup form to rectify the username input field if input username is not available.
This tutorial shows how to check username availability using Servlet, AJAX and MySQL. So after finishing this example you will be able to apply the same logic to any Servlet based web framework or any server side technologies such as PHP, Codeigniter etc. Continue reading “Username availability check using Servlet, AJAX and MySQL”