Code To Accept Numbers and Strings in Text box using Javs Script

        function keyInputsAlphabetsAndNumbers(evt) {

            var charCode;
            if (window.event)
                charCode = window.event.keyCode;  //for IE
            else
                charCode = evt.which;  //for firefox
            if (charCode == 32) //for <space> symbol
                return false;
            if (charCode > 31 && charCode < 48) //for characters before 'A' in ASCII Table
                return false;
            if (charCode > 90 && charCode < 97) //for characters between 'Z' and 'a' in ASCII Table
                return false;
            if (charCode > 122) //for characters beyond 'z' in ASCII Table
                return false;
            return true;
            }


In Asp.net :-



  <asp:TextBox ID="txtLoginName" runat="server"  CssClass="TextBox" Width="150px" TabIndex="1"    AutoCompleteType="Disabled"  onkeypress="return keyInputsAlphabetsAndNumbers(event);"  ></asp:TextBox>