let today = new Date().toISOString().slice(0, 10)
const startDate = '2021-04-15';
const endDate = today;
const diffInMs = new Date(endDate) - new Date(startDate)
const diffInDays = diffInMs / (1000 * 60 * 60 * 24);
alert( diffInDays );function calculateDaysBetweenDates(date1, date2) {
var oneDay = 24 * 60 * 60 * 1000;
var date1InMillis = date1.getTime();
var date2InMillis = date2.getTime();
var days = Math.round(Math.abs(date2InMillis - date1InMillis) / oneDay);
return days;
}const dayDif = (date1, date2) => Math.ceil(Math.abs(date1.getTime() - date2.getTime()) / 86400000)
dayDif(new Date("2020-10-21"), new Date("2021-10-22"))
// Result: 366
const diffDays = (date, otherDate) => Math.ceil(Math.abs(date - otherDate) / (1000 * 60 * 60 * 24));
// Example
diffDays(new Date('2014-12-19'), new Date('2020-01-01')); // 1839/* difference between date1 and date2 in days (date2 - date1) */
/* date1 and date 2 are already javascript date objects */
function dateDifference(date2, date1) {
const _MS_PER_DAY = 1000 * 60 * 60 * 24;
// Discard the time and time-zone information.
const utc1 = Date.UTC(date1.getFullYear(), date1.getMonth(), date1.getDate());
const utc2 = Date.UTC(date2.getFullYear(), date2.getMonth(), date2.getDate());
return Math.floor((utc2 - utc1) / _MS_PER_DAY);
}