Restrict space in textbox using JavaScript.

<script type = "text/javascript">
        function Disable_Space() 
        {
            if(event.keyCode == 32)
            {
                event.returnValue = false;
                return false;
            }
        }
    </script>

<asp:TextBox ID = "txt_user_id" onkeypress = "return Disable_Space();" 
runat = "server"></asp:TextBox>