*Format US Phone Numbers.md

Two options to format US phone numbers

Loops and Logic
Use Loops and Logic's regex feature using capture groups to grab the parts, then insert . or - when reassembling the capture groups

Javascript
Using JS to extract (slice) the phone number into separete parts, inject the . or - and reassemble

Format US Phone Number with Loops and Logic.html

<!-- Format phone number with L&L regex -->
<Format replace_pattern="/(\d{3})(\d{3})(\d{4})/" with="$1.$2.$3"><Field phone_number /></Format>

<!-- An example of this in use -->
<a href="tel:{Field phone_number /}{If field=phone_extension};{Field phone_extension /}{/If}">
    <span class="phone-number"><Format replace_pattern="/(\d{3})(\d{3})(\d{4})/" with="$1.$2.$3"><Field phone_number /></Format></span>
    <If field="phone_extension">
    <span class="phone-extension">ext.<Field phone_extension /></span>
    </If>
</a>

Format US Phone Number with Loops and Logic.js

jQuery(document).ready(function($) {

    // Find all elements with class "phone-number"
    $('.phone-number').each(function() {
        // Get the phone number from the element
        var phoneNumber = $(this).text().trim();
        
        // Format the phone number
        var formattedPhoneNumber = phoneNumber.slice(0, 3) + '.' + phoneNumber.slice(3, 6) + '.' + phoneNumber.slice(6);
        
        // Update the content of the element with the formatted phone number
        $(this).text(formattedPhoneNumber);
    });

});