michael@0: datediff = function(date1, date2, interval) {
michael@0:   var delta = 1;
michael@0:   switch(interval) {
michael@0:   case "day":
michael@0:     delta /= 24;
michael@0:   case "hour":
michael@0:     delta /= 60;
michael@0:   case "minute":
michael@0:     delta /= 60;
michael@0:   case "second":
michael@0:     delta /= 1000;
michael@0:   case "millisecond":
michael@0:     delta *= date2.getTime() - date1.getTime();
michael@0:   }
michael@0:   return Math.round(delta);
michael@0: };
michael@0: 
michael@0: var diff = datediff(new Date("2012-04-28T14:30:00Z"), new Date("2012-04-29T14:30:00Z"), "day"); 
michael@0: for (var i = 0; i < 50; i++) {
michael@0:   diff = datediff(new Date("2012-04-28T17:00:00Z"), new Date("2012-04-28T17:30:00Z"), "minute"); 
michael@0:   assertEq(diff, 30);
michael@0: }