function counterUpdate(opt_countedTextBox, opt_countBody, opt_maxSize) {
        var countedTextBox = opt_countedTextBox ? opt_countedTextBox : "comments";
        var countBody = opt_countBody ? opt_countBody : "countBody";
        var maxSize = opt_maxSize ? opt_maxSize : 300;

        var field = document.getElementById(countedTextBox);

        if (field && field.value.length >= maxSize) {
                field.value = field.value.substring(0, maxSize);
        }
        var txtField = document.getElementById(countBody);
                if (txtField) {
                txtField.innerHTML = "You have " + (maxSize-field.value.length) + " characters left";
        }
}