JavaScript - Methods

Date.parse()
If you have a valid date string, you can use the Date.parse() method to convert it to milliseconds. Date.parse() returns the number of milliseconds between the date and January 1, 1970. You can then use the number of milliseconds to convert it to a date object.

Date.toUTCString() / Date.toLocaleString() /
Return the time portion of a Date object as a string, using locale conventions.

let utcDate = new Date("2011-06-29T16:00:00.000z");
document.getElementById("demo3").innerHTML = `utcDate: ${utcDate.toUTCString()}`;
document.getElementById("demo4").innerHTML = `converted to local: ${utcDate.toLocaleString()}`;
document.getElementById("demo5").innerHTML = `converted to utc: ${utcDate.toUTCString()}`;

let stringDate = "April 30, 1970";
let dateInMilliseconds = Date.parse(stringDate);
let birthDate = new Date(dateInMilliseconds);
document.getElementById("demo1").innerHTML = birthDate;

Compare Dates
Dates can easily be compared. The following example compares today's date with January 14, 2100.

let date1 = new Date(1970, 04, 30);
let date2 = new Date(1969, 05, 13);
let message = "";

if (date2 < date1)
{
    message="Lisa is older.";
}