calculate years between two dates code example

Example 1: calculate days between dates

let startDate = "2021-04-01";
let date1 = new Date();
let date2 = new Date(startDate);
let timeInMilisec = date1.getTime() - date2.getTime();
let daysBetweenDates = Math.ceil(timeInMilisec / (1000 * 60 * 60 * 24));

Example 2: How to calculate the difference between two dates

$datetime1 	= new DateTime('2020-10-11 16:52:52');
$datetime2 	= new DateTime('2020-10-13 16:52:52');
$interval 	= $datetime1->diff($datetime2);

echo $interval->format('%a days');