If so, it allows it to be submitted to the server and (usually) saved in a database; if not, it gives you error messages to explain what you've done wrong (provided you've done it right).
Java Script provides a way to validate form's data on the client's computer before sending it to the web server. First let us see how to do a basic form validation.
First, download the Java Script form validation script here.
More and more browsers now support the constraint validation API, and it's becoming reliable.
This API consists of a set of methods and properties available on each form element.