JavaScript provides a built-in Date object to work with dates and times — including year, month, day, hour, minutes, seconds, and milliseconds.

 How to Create Dates

 1. Current Date and Time

    var currentDate = new Date(); // Creates a date object with the current date and time

 2. Using a Date String

    var date1 = new Date("March 3, 2015");
    var date2 = new Date("2015-03-03 10:30:00");

 3. Using Milliseconds from 1970

    var date1 = new Date(0);      // Jan 1, 1970
    var date2 = new Date(1000);   // 1 second after Jan 1, 1970

4. Using Year, Month, Day, etc.

    var date = new Date(2021, 1, 3); // Month is 0-based: 1 = February
    var date2 = new Date(2021, 1, 3, 10, 30, 45); // With time

Month Index Starts from 0 ? January = 0, February = 1, ..., December = 11

Date Formats

JavaScript supports ISO 8601 date format:

    var date = new Date('2015-02-10T10:12:50.500Z');

Other examples of accepted formats:

    new Date("3/2/2015");        // MM/DD/YYYY
    new Date("3 February, 2015");
    new Date("February 3 2015");

 Some formats may not work consistently across browsers — prefer standard formats like YYYY-MM-DD.

Convert Date Formats

Once you have a date object, you can convert it to different formats:

    var date = new Date('2015-02-10T10:12:50.500Z');

    date.toDateString();         // "Tue Feb 10 2015"
    date.toLocaleDateString();   // "2/10/2015"
    date.toGMTString();          // "Tue, 10 Feb 2015 10:12:50 GMT"
    date.toISOString();          // "2015-02-10T10:12:50.500Z"
    date.toLocaleString();       // "2/10/2015, 10:12:50 AM"
    date.toLocaleTimeString();   // "10:12:50 AM"
    date.toTimeString();         // "10:12:50 GMT+0000"
    date.toUTCString();          // "Tue, 10 Feb 2015 10:12:50 GMT"

Custom Date Format (DD-MM-YYYY)

You can manually format the date:

    var date = new Date('4-1-2015'); // MM-DD-YYYY

    var day = date.getDate();
    var month = date.getMonth() + 1;
    var year = date.getFullYear();

    var dateString = 
    (day < 10 ? '0' + day : day) + '-' +
    (month < 10 ? '0' + month : month) + '-' + 
    year;

    console.log(dateString); // 01-04-2015

Compare Dates

You can compare two dates using <, >, ==, etc.

    var date1 = new Date('4-1-2015');
    var date2 = new Date('4-2-2015');

    if (date1 > date2) {
    console.log("date1 is later");
    } else if (date1 < date2) {
    console.log("date1 is earlier");
    } else {
    console.log("dates are the same");
    }

 Dates are compared by their numeric timestamp behind the scenes.

 Summary Table

Tips

• Always use new Date() to create a date object.

• Prefer ISO format (YYYY-MM-DD) for compatibility.

• Remember that months are zero-based (Jan = 0).

• Use libraries like Moment.js or date-fns for advanced formatting and manipulation.