I have a query about web development. Don't have development knowledge and trying build a web application.
The requirement is:
When the user clicks a submit button after enter data in 2-3 html input textboxes, I would like to pop-up a confirmation dialog based on results from some java code e.g. if the data entered is already existing in server, I would like to ask: "Hey! this data is already there. Are you sure you wanted merge the input with existing data?".
I am not sure how I can do it. I am using Java, Tomcat, Eclipse, JSP, HTML, Javascript in my application. I know I can invoke javascript functions on click of button, but how to generate a confirmation dialog based on some processing of the input data, and based on confirmation, go ahead with full processing.