function js_numeric(field, name)
{
    if (document.getElementById(field).value.length>0 && isNaN(document.getElementById(field).value)) {
        document.getElementById(field).style.backgroundColor = "#FFCCFF";
        if (name=="")
            alert("This field must contain a numeric value.");
        else
            alert(name + " must contain a numeric value.");
        document.getElementById(field).focus();
        return false;
    }

    document.getElementById(field).style.backgroundColor = "white";
    return true;
}