Validating phone number
This is a great way to validate the input since the user will be notified before submitting the data if it is valid or not.
The problem with validating user input on the client side is that there is no security.
This not only creates a standardized string that can be later used in a comparison or stored in a database, but also ensures that the data that is received on the server end contains only the expected data.
This is important because most website attacks are caused by accepting user input blindly.
There are many different ways a user might input a phone number.
Sometimes they may choose to input it as, (555) 555-5555. As a developer we never really know how they might input the number.
Often times we can give our users an example and they will still enter the wrong format.
Similarly if we want to validate phone number like xxx-xxx-xxxx format then you can use “\d-\d-\d”.Identify whether a phone number is a landline, free phone, Vo IP phone, or even a mobile phone.This lets you not only target a mobile outreach campaign to either SMS or telephone, but also consider the type of phone in order to remain compliant with regulations such as the Telephone Consumer Protection Act (TCPA).Regular expressions are a right way to validate text fields such as phone numbers, names, addresses, age, date and other input information.You can use them to constrain input, apply formatting rules, and check lengths.