It has an onsubmit event attached to a function called validate() that we are going to create later inside this form there are three inputs one for our phone number another one is for postal codes and the third and the last one is a submit button that is going to submit the form after we are done filling it. It contains only the code that validates the phone number.In the first line, I am using Element By Id() to grab the phone number from the input element.First, let’s start by building the webpage and the validation code then we will talk about the regular expressions used to validate the strings.First go to your html file and paste the following code : Here, I have a simple form.When there are many fields in the form, the Java Script validation becomes too complex.The Java Script class presented here makes the form validations many times easier.
This validation descriptor is valid only for drop down lists.
The script has a catalog of almost all the common validation types built-in.
The idea is to create a set of “validation descriptors” associated with each element in a form.
In this tutorial you will see how to use regular expressions to validate.
Through a list of examples , we will build a script to validate phone numbers , UK postal codes, along with more examples.
In this all the inputs are mandatory and email address entered should be in correct format.