Military Clock Converter but in JavaScript

// Test here: https://rextester.com/l/js_online_compiler

var seconds = 34534345;
var minutes = 0;
var hours = 0;
var days = 0;
var years = 0;

while (seconds >= 60) {
    seconds-=60;
    minutes++;
}

while (minutes >= 60) {
    minutes-=60;
    hours++;
}

while (hours >= 24) {
    hours-=24;
    days++;
}

while (days >= 365) {
    days-=365;
    years++;
}

// LINE OF STRINGS ------------------------------------

if (years < 10) {
    years = years.toString();
    years = "0"+years;
}
if (days < 10) {
    days = days.toString();
    days = "0"+days;
}
if (hours < 10) {
    hours = hours.toString();
    hours = "0"+hours;
}
if (minutes < 10) {
    minutes = minutes.toString();
    minutes = "0"+minutes;
}
if (seconds < 10) {
    seconds = seconds.toString();
    seconds = "0"+seconds;
}

print("yy:dd:hh:mm:ss")
print(years+":"+days+":"+hours+":"+minutes+":"+seconds)