javascript - Division of decimal part of number only -

is there anyway divide decimal of number instead of whole number. if have number 3.99 want divide decimal 1.66667. want because 3.99 supposed equal 3 minutes 59 seconds, rather have read 3.59 instead of 3.99.

this code have return time now, btw returning time program telling how time till due. used full 2 decimal number format.

function getdiff(dt) {      smins = " min";     shours = " hours";     sdays = " days";     ssecs = " secs";      if (math.abs(datediff("s", now, dt)) < 86400) {         if (math.abs(datediff("s", now, dt)) <= 3600) {             return ((math.floor(math.abs(                      datediff("s", now, dt) / 60) * 100) / 100                      ).tofixed(2) + smins);         }         else         {             return ((math.floor(math.abs(                      datediff("s", now, dt) / 3600) * 100) / 100                      ).tofixed(2) + shours);         }     }     else     {         return ((math.floor(math.abs(                  datediff("s", now, dt) / 86400) * 100) / 100                  ).tofixed(2) + sdays);     } } 

you minutes - 3, , 0.99 minutes 0.99*60 seconds , append minutes return "3"+"."+"59" + smins

but not recommended display "." case....