Счётчик символов: <input value=" " id="num" class="codeButtons"
readonly="true" style="width: 40px; text-align: center;" title="Счётчик
символов" type="text">

<SCRIPT type=text/javascript>
document.getElementById("main-reply").addEventListener('focus', nc, false);
document.getElementById("main-reply").addEventListener('keydown', nc, false);
document.getElementById("main-reply").addEventListener('keyup', nc, false);
document.getElementById("main-reply").addEventListener('keypress', nc, false);
document.getElementById("main-reply").addEventListener('change', nc, false);
function nc(){document.getElementById('num').value = document.getElementById('main-reply').value.length}   
</SCRIPT>