phone number validator js

How Can i allow the function to modify and print the number only if it is of the following format: +XX-XXXX-XXXX ? This is the code that allows invalid phone numbers like simple text

function updatePhone() {
    var phoneNumbers = "";
    var additionalPhoneNumber = $('#phoneInputAdditional').val() + ",";
    $('.phoneInput').each(function () {
        if ($(this).val() != "")
            phoneNumbers = phoneNumbers + $(this).val().toString() + ",";
        console.log($(this).val());
    });
    if (additionalPhoneNumber != ",")
        phoneNumbers = phoneNumbers + additionalPhoneNumber;

    phoneNumbers = phoneNumbers.substring(0, phoneNumbers.length - 1);

    $.ajax({
        type: "POST",
        url: "/updatePhone",
        data: {"phoneNumbers": phoneNumbers},
        dataType: "json"
    })
        .done(function (response) {
            $("#userPhone").text('Phone: ' + response[0]);
            $("#phoneul").empty();
            for (var i = 1; i < response.length; i++)
                $("#phoneul").append('<li class = "col-sm-4 phoneli"> <b>Update Number:</b> <input type = "text" value ="' + response[i] + '" class= "form-control phoneInput"/></li>')
            $("#phoneul").append('<li class="col-sm-4"><b>Additional Number:</b> <input type = "text" placeholder = "Another Phone Number" class="form-control" id= "phoneInputAdditional"/></li>')
            $("#good3").show();
                setTimeout(function(){ $("#good3").hide(); }, 800);
        })
        .fail(function () {
            $("#bad3").show();
        });
}