Phone no. field validation in Account and contact module

How to validate phone no. and email field ?Phone no is valid or not?

@Jamshy_EK

  1. In frontend - you can write and load javascript to the form editview.
  2. In backend - you can write logichook.

I want in frontend.can you share the file name

@Jamshy_EK
For example look at the lines of file - modules/Contacts/metadata/editviewdefs.php

...
            'includes' => array (
                0 => 
                array (
                    'file' => 'include/javascript/tiny_mce/tiny_mce.js',
                ),
            ),
...

You can:

  1. Copy file of your <module_name> to custom/modules/<module_name>/metadata
  2. Add file with your code as a new record of array.

Documentation here: https://docs.suitecrm.com/developer/metadata/