One of the most practical uses of JavaScript is validating forms.
Lets first define what is meant by validating forms.
Well, using JavaScript, you can check what a user enters into a form, intercept a form from being submitted and ask the user to retype or fill in the unfilled entries of a form before re-submission. Using the onBlur event handler We will now introduce two more event handlers, ones especially for forms, that are used commonly when doing form validations. Executes JavaScript whenever a user moves with the mouse the focus away from an element within a form. In other words, whenever a person first clicks an element, and then clicks anywhere outside of it. Ok, you need clarification.