https://joeverde.com/js/demo.js

1/*$("#phone").intlTelInput({
2  utilsScript: "http://www.joeverde.com/js/utils.js"
3})*/
4
5var telInput = $("#phone"),
6  //validMsg = $("#valid-msg"),
7    errorMsg = $("#error-msg");
8
9// initialise plugin
10telInput.intlTelInput({
11  utilsScript: "https://www.joeverde.com/js/utils.js"
12});
13
14var reset = function() {
15  telInput.removeClass("error");
16  //errorMsg.addClass("hide");
17  document.getElementById('error-msg').innerHTML ="";
18 // validMsg.addClass("hide");
19};
20
21// on blur: validate
22telInput.blur(function() {
23  reset();
24  if ($.trim(telInput.val())) {
25    if (telInput.intlTelInput("isValidNumber")) {
26      //validMsg.removeClass("hide");
27    } else {
28      
29	  /* var form = document.getElementById("contactform");
30
31		 form.addEventListener("submit", function (ev) {
32				  ev.preventDefault();
33		 });*/
34	  
35	  telInput.addClass("error");
36      //errorMsg.removeClass("hide");
37	  document.getElementById('error-msg').innerHTML ="Invalid Phone Number";
38    }
39  }
40});
41
42// on keyup / change flag: reset
43telInput.on("keyup change", reset);