It is important to validate the form submitted by the user because it can have inappropriate values. The Java Script provides you the facility the validate the form on the client side so processing will be fast than server-side validation.
So, most of the web developers prefer Java Script form validation.
In this example, we are going to validate the name and password.It can prevent people from leaving fields blank, from entering too little or too much or from using invalid characters.For an alternative approach to client-side form validation, without Java Script, check out our new article on HTML5 Form Validation which is available now in most modern browsers.For example, you can have an input field that should not be empty, should be less than 25 chars and should be alpha-numeric. In some dynamically programmed pages, it may be required to change the validations in the form at run time.In this document, we have discussed Java Script Form Validation using a sample registration form.