JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://jquery-joshbush.googlecode.com/files/jquery.maskedinput-1.2.2.js"></script>
Phone: <input class="phone"/><br/>
Zip: <input class="zip"/>

<select id="country" name="country" class="country">
<option selected="selected" value="0"></option>
<option value="CA">Canada</option>
<option value="US">United States</option>
</select>

<input type="text" class="postal_code" name="postal_code" />

JavaScript

$(".phone").mask("(999)-999-9999");
$(".zip").mask("99999?-9999");


$('#country').change(function () {
    //alert($('#country option:selected').val());
    if ($('#country option:selected').val() == 'US') {
       $(".postal_code").unmask("")
        $(".postal_code").mask("99999");
         //alert(' yea ');
    } else {
        $(".postal_code").mask("a9a-9a9");
    }
});