Count Charactes in a TextBox by using JavaScript.

<asp:TextBox ID="txt_message" runat="server" CssClass="textarea" Height="100px" onkeyup="validatelimit(this)" TextMode="MultiLine" Width="250px"></asp:TextBox>

//Key Press Event

 function validatelimit(obj)

 {

    if(this.id)

    obj=this;   

    var i=obj.value.length;

    document.getElementById('<%= lbl_ccount.ClientID %>').innerHTML=i;

    if(1>0)

    {

        var q=i/160;

        var r=i%160;       

         if(r==0)

         {

            q=Math.round(q);

            document.getElementById('<%= lbl_mcount.ClientID%>').innerHTML=q;

         }

         else

         {

           q=Math.floor(q);                   

           document.getElementById('<%=lbl_mcount.ClientID%>').innerHTML=q+1;

          }   

       }

    else

    {

        document.getElementById('<%= lbl_mcount.ClientID %>').innerHTML=0;

    }

 }