javascript in asp net

See more:

C#

ASP.NET

Hello all

I created a how to count the character left to type

The JavaScript code is

<script type="text/javascript" language="javascript">
    function validatelimit(obj, maxchar)
     {
        if (this.id) obj = this;
        var remaningChar = maxchar - obj.value.length;
        document.getElementById('<%= Label1.ClientID %>').innerHTML = remaningChar;
        if (remaningChar <= 0) {
            obj.focus();
            obj.value = obj.value.substring(maxchar, 0);
            alert('Character Limit exceeds!');
            return false;
        }
        else
        { return true; }
    }
</script>

In asp source file,

<asp:TextBox ID="txt_Skill" runat="server" TextMode="MultiLine" onkeyup="validatelimit(this,50)"></asp:TextBox>

It is working but when i am refreshing the page that time the label contains the maxvalue as 255.

I want how i disable the writing character after 255 no of character.

Any body help me