Example: European countries

Set onlyCountries option to just European country codes.

Markup

<input id="phone" type="tel">

Code

$("#phone").intlTelInput({
  onlyCountries: ["al", "ad", "at", "by", "be", "ba", "bg", "hr", "cz", "dk", 
  "ee", "fo", "fi", "fr", "de", "gi", "gr", "va", "hu", "is", "ie", "it", "lv", 
  "li", "lt", "lu", "mk", "mt", "md", "mc", "me", "nl", "no", "pl", "pt", "ro", 
  "ru", "sm", "rs", "sk", "si", "es", "se", "ch", "ua", "gb"],
  utilsScript: "../../lib/libphonenumber/build/utils.js" // just for formatting/placeholders etc
});

Result