find the date difference code example
Example 1: 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');
Example 2: date difference
function daysBetween(first, second) {
var one = new Date(first.getFullYear(), first.getMonth(), first.getDate());
var two = new Date(second.getFullYear(), second.getMonth(), second.getDate());
var millisecondsPerDay = 1000 * 60 * 60 * 24;
var millisBetween = two.getTime() - one.getTime();
var days = millisBetween / millisecondsPerDay;
return Math.floor(days);
}