I had the same problem, this is what I ended up doing:
function parseMillisecondsIntoReadableTime(milliseconds){_x000D_
//Get hours from milliseconds_x000D_
var hours = milliseconds / (1000*60*60);_x000D_
var absoluteHours = Math.floor(hours);_x000D_
var h = absoluteHours > 9 ? absoluteHours : '0' + absoluteHours;_x000D_
_x000D_
//Get remainder from hours and convert to minutes_x000D_
var minutes = (hours - absoluteHours) * 60;_x000D_
var absoluteMinutes = Math.floor(minutes);_x000D_
var m = absoluteMinutes > 9 ? absoluteMinutes : '0' + absoluteMinutes;_x000D_
_x000D_
//Get remainder from minutes and convert to seconds_x000D_
var seconds = (minutes - absoluteMinutes) * 60;_x000D_
var absoluteSeconds = Math.floor(seconds);_x000D_
var s = absoluteSeconds > 9 ? absoluteSeconds : '0' + absoluteSeconds;_x000D_
_x000D_
_x000D_
return h + ':' + m + ':' + s;_x000D_
}_x000D_
_x000D_
_x000D_
var time = parseMillisecondsIntoReadableTime(86400000);_x000D_
_x000D_
alert(time);
_x000D_