Script to Count text length in textbox

<script type="text/javascript">

    function ismaxlength(objTxtCtrl, nLength) {

        if (objTxtCtrl.getAttribute && objTxtCtrl.value.length > nLength)

            objTxtCtrl.value = objTxtCtrl.value.substring(0, nLength)

        if (document.all)

            document.getElementById('<%= lblCaption.ClientID %>').innerText = objTxtCtrl.value.length + ' daripada ' + nLength;

        else

            document.getElementById('<%= lblCaption.ClientID %>').textContent = objTxtCtrl.value.length + ' daripada ' + nLength;

    }

</script>

<asp:TextBox ID="txtNote" runat="server" Width="381px" Rows="3" onkeyup="return ismaxlength(this,250)"

                    TextMode="MultiLine"  ></asp:TextBox> <br />

<asp:Label runat="server" ID="lblCaption" Font-Bold="True" Visible="True">