// function parameters are: field - the string field, count - the field for remaining characters number and max - the maximum number of characters
        function CountLeft(field, count, max) 
        {
            // if the length of the string in the input field is greater than the max value, trim it
            if (field.value.length > max)
                field.value = field.value.substring(0, max);
            else
            // calculate the remaining characters
                count.value = max - field.value.length;
        }