How can i disable the past dates and 5 future date ?

I would like to know how i can disable the future dates. Eg, Today is 6July, it will disable the past dates + 5 of the future dates = 10July.
Thank you in advance.


<script type="text/javascript">
              function checkDate(sender, args) {
                  if (

                      sender._selectedDate < new Date.AddDays(5)); {
                      alert("You cannot select a day earlier than today!");
                      sender._selectedDate = new Date.AddDays(5);
                      // set the date back to the current date
                      sender._textbox.set_Value(sender._selectedDate.format(sender._format))
                  }
              }</script>

<script type="text/javascript">// </script>