Regex for validating international phone numbers
If we wanted to do that, we could create three (or four) form fields (one for each element) and restrict the length of those fields.
Then, on the server-side, we’d piece them together.
The following method may still be used for that approach, but it is a powerful tool intended to validate phone numbers from sources that are well beyond control.
Take a text file of customer data from an electric utility, for example.
For that, I will use libphonenumber, Phone number parsing, validation and formatting may be important in some scenarios.
The expression looks like this: Now that we have an expression that will work some magic and validate a phone number, let’s see how to put it into action.
You can now take each of these elements and format the number as you wish so that all the numbers in the database will follow the same pattern.
Likewise, you could have a free form field – rather than three separate fields – on a Web page for users to enter a phone number.
Before we do that, though, let me digress and explain what’s going to happen in this validation process.
We don’t just want to validate user input to ensure a user has entered a phone number in a proper format.