function clearValue(objElement, strCheckValue) {

    //  check that the value has not been changed before clearing.
    if (objElement.value == strCheckValue) {
        objElement.value = '';
    }
}

function dropDown(strElementID, bVisible, strDropDownHeader) {

    //  handle drop down elements.
    var objDropDown = document.getElementById(strElementID);
    if (bVisible == true) {
        objDropDown.style.display = "block";
    } else {
        objDropDown.style.display = "none";
    }

    //  handle headers if necessary.
    if ( strDropDownHeader != null ) {
        var objDropDownHeader = document.getElementById(strDropDownHeader);
        if (bVisible == true) {
            objDropDownHeader.className = "on";
        } else {
            objDropDownHeader.className = "off";
        }
    }
}