Character Counter for Multiline Textbox

Does anyone know how to modify the javascript below in order for this character counter to work with a multiline textbox rather than a textarea?

This is the control I want to use:

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<asp:TextBox id="Description2" runat="server" Height="136px" Width="352px" TextMode="MultiLine"
                  MaxLength="255"></asp:TextBox>
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This is the script and html that is working:

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<script language="Javascript">

function taLimit() {
      var taObj=event.srcElement;
      if (taObj.value.length==taObj.maxLength*1) return false;
}

function taCount(visCnt) {
      var taObj=event.srcElement;
      if (taObj.value.length>taObj.maxLength*1) taObj.value=taObj.value.substring(0,taObj.maxLength*1);
      if (visCnt) visCnt.innerText=taObj.maxLength-taObj.value.length;
}
</script>

<form id="Form1" method="post" runat="server">
         <table>
      <tr>
            <td>
                            <font>Maximum Number of characters for this text box is 255.<br>
                                     <TEXTAREA runat="server" onkeypress="return taLimit()" onkeyup="return taCount                     (myCounter)"  name="Description" rows="7" wrap="physical" cols="40" maxLength="255"></TEXTAREA>
<br>
                        You have <B><SPAN id="myCounter">255</SPAN></B> characters remaining for your description...</font>
                     </td>
              </tr>
 </table>
</form>

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