This works in FF and Chrome as suggested by
this discussion
<textarea name="textarea" id="txtComments" rows="3" onkeyup='return fnMaxLength(this,"5");' style="width: 940px" ></textarea>
function fnMaxLength(field, maxChars) {
if (field.value.length >= maxChars) {
var object = "-More than " + maxChars + " characters have been entered.";
//errorAlert("error", "Maximum length error", object);
alert(object);
return false;
}
}