I am getting this error when i run this function

```
<script language="javascript" type="text/javascript">
        //function for check digit
    function check_no(e)
         {
             if (!((e.keyCode >= 48) && (e.keyCode <= 53)))
             {
                 alert("Solo valores entre 0 y 5 pueden ser ingresados");
                 e.keyCode = 0;
             }
         }
</script>

```

I call the function in my load page in c#

```
foreach (GridViewRow grdrow in DGPlanilla.Rows)
                {
                    TextBox tb1 = (TextBox)grdrow.FindControl("TextBox1");
                    if (tb1 != null)
                    {
                        tb1.Attributes.Add("Onkeypress", "check_no()");
                    }

                }

```