Complete Form Validation JavaScript Part 5

<style type="text/css">
    .success_brd{
        border:1px solid green
    }
</style>

<script type="text/javascript">
//////////////// This update checks all empty fields ////////////
    //function checks for empty fields
    function CheckEmpty(field_id){
        var MyValue = document.getElementById(field_id);
        if(MyValue.value == "" || MyValue.value == null){
            //code
            displayWarning(field_id, MyValue.parentNode.id, "You can't leave this empty.");
        }
        else {
            removeWarning(field_id, MyValue.parentNode.id);
        }
    }

//////////////// This update will validate the checkbox ////////////
//function checks the checkboxes
    function ValidateCheckbox(checkbox){
        var check_box = document.getElementById(checkbox);
        if(check_box.checked == false){
            //code
            displayWarning(checkbox, check_box.parentNode.parentNode.id, "You must agree to proceed.");
        }
        else {
            removeWarning(checkbox, check_box.parentNode.parentNode.id);
        }
    }

//////////////// This is an update to confirm the selection list ////////////
    //function validates the selections
    function ValidateSelect(select){
        //code
        selected = document.getElementById(select);
        if(selected.selectedIndex == 0){
            //code
            displayWarning(select, selected.parentNode.id, "Please select your country.");
        }
        else {
            removeWarning(select, selected.parentNode.id);
        }
    }

//////////////// This is a new function ////////////
    //function remove error message
    function removeWarning(field_id, parent_div){
        var error_element = document.getElementById(parent_div).querySelectorAll(".warning_msg");
        if (error_element.length > 0){
            error_element[0].parentNode.removeChild(error_element[0]);
            document.getElementById(field_id).classList.remove("warning_brd");

        }
        document.getElementById(field_id).className += " success_brd";
    }
</script>