adding if statement to function

adding if statement to function

This one must seem simple for most of you, but its not for me so any help
would be appreciated. How do I add if statements to my function to do this
if ms is > than 86400000 return clock : days + " " + hours if its > than
3600000 return clock : hours + ":" + minutes. Here is what I have so far.
if ( DateDiff ("ms", now, TestDue) >= 0 ) {
var Date1 = new Date();
var Date2 = Date.parse(Date1);
var TestLate1 = Date.parse(TestLate);
var TestDue1 = Date.parse(TestDue);
var TestLate2 = convertMS(TestLate1 - Date2).clock;
var TestDue2 = convertMS(TestDue1 - Date2).clock;
var TestDiff = convertMS(TestLate1 - TestDue1).clock;
tto = "../Images/Blue-120-Button.png";
ttt = "Test Start " + TestDue2;
ttm = "../Images/Blue-120-ButtonMouseOver.png";
ttd = "Test will start in " + TestDue2
+ ", will be due in " + (TestDiff) + "
after that and will be late on " +
TestLate + ".";
C3color = "#FFFFFF";
C3Mcolor = "#FFFF00";
ASTRIS = "../Images/BlueTestB.png";
ASTRIS2 = "../Images/BlueTestB2.png";
so that's the part of the function I need to implement different times for.
function convertMS(ms) {
days = Math.floor(ms / 86400000), // 1 Day = 86400000 Milliseconds
hours = Math.floor((ms % 86400000)/ 3600000), // 1 Hour = 3600000
Milliseconds
minutes = Math.floor((ms % 3600000) / 60000), // 1 Minutes = 60000
Milliseconds
seconds = Math.floor(((ms % 360000) % 60000) / 1000) // 1 Second = 1000
Milliseconds
if (minutes.toString().length == 1 ) {minutes = "0" + minutes};
if (seconds.toString().length == 1 ) {seconds = "0" + seconds};
return {
days : days,
hours : hours,
minutes : minutes,
seconds : seconds,
clock : days + " " + hours + ":" + minutes + ":" + seconds
};
}