help me to extend this code

[Stylewriter]

hi!
I need help to extend this code that it will show the days to.
it works with showing the hours, minutes and seconds.
but I don't get it to work with days...
I hope you are able to help me!

here is the code - what I've done by now:

<SCRIPT LANGUAGE="JavaScript">
                           <!--
                           var restzeit = new Number();
                           var restzeit =<?php echo "$rest"; ?>;
                           function startCountdown()
                            {
                              if((restzeit - 1) >= 0)
                                   {
                                      restzeit = restzeit - 1;
                                      var min_count = restzeit/60;
                                      min_count=Math.floor(min_count);
                                      sec_count = restzeit - (min_count*60);
                                      if(min_count>0) 
                                           {
                                               var std_count = min_count/60;
                                               std_count=Math.floor(std_count);
                                               min_count=min_count-std_count*60;
                                           }else
                                           {
                                               var std_count = 0;
                                           }
                                               if(min_count<10)
                                           {
                                               min_angabe='0'+min_count;
                                           }else
                                           {
                                               min_angabe=''+min_count;
                                           }
                                      if(sec_count<10)
                                           {
                                               sec_angabe='0'+sec_count;
                                           }else
                                           {
                                               sec_angabe=''+sec_count;
                                           }
                                      verbleibend.innerText = std_count+' h |'+min_angabe+' min |'+sec_angabe;
                                      setTimeout('startCountdown()',986);
                                   }else
                                   {
                                      verbleibend.innerText = '0:00:00';
                                      setTimeout('history.go()',5000);
                                   }
                              }
                              //  End -->
</SCRIPT>