JavaScript - Validations

It is important to validate the form submitted by the user because it can have inappropriate values. So, validation is must to authenticate user.

JavaScript provides facility to validate the form on the client-side so data processing will be faster than server-side validation. Most of the web developers prefer JavaScript form validation.

There are several ways to perform validations in JavaScript, including:

1. Client-side Validation: This involves checking the user input on the client side (the browser) using JavaScript before the form is submitted. This provides instant feedback to the user and can save time by avoiding server round trips.
2. Server-side Validation: This involves checking the user input on the server after the form is submitted. This provides a more secure method of validation since the user cannot manipulate the validation code on the client side.

Common validation techniques include checking for required fields, validating data formats (such as email addresses or phone numbers), checking the length of input, and comparing values to ensure they match a specific pattern or requirement.