<div class="form-group form-inline phone">
    <label class="col-sm-2 control-label">Phone</label>
    <div class="col-sm-10">
        <input type="text" class="form-control" id="phonetype1" placeholder="Type of Phone">
        <input type="text" class="form-control" id="number1" placeholder="Write here your phone number">
    </div>
</div>
<span id="newPhone"> Add a phone number</span>

$("#newPhone").on('click',function(){
    var numItems = $('.phone').length +1;
    var newPhone=  '<div class="form-group form-inline phone">';
    newPhone+= '<label class="col-sm-2 control-label"></label>';
    newPhone+= '<div class="col-sm-10">';
    newPhone+= '<input type="text" class="form-control" id="phonetype'+numItems+'" placeholder="Type of Phone">';
    newPhone+= '<input type="text" class="form-control" id="number'+numItems+'"" placeholder="Write here your phone number">';
    newPhone+= '</div> </div>';
    $(this).before(newPhone);
});

$(function()
{
    $("input").on('blur',function(){
        var formElementId = $(this).attr("id");
        validateField(formElementId); //This function works, for sure
    });
});

$("form").on('blur','input',function(){
    var formElementId = $(this).attr("id");
    validateField(formElementId); //This function works, for sure
});