JavaScript date output format will be a full format date string
ISO 8601 is international standard for date and time format
It is written as YYYY-MM-DD format
<!DOCTYPE html>
<html>
<body>
<span id="date"></span>
<script>
var d = new Date("2016-06-04");
document.getElementById('date').innerHTML=d;
</script>
</body>
</html>
ISO 8601 dates can be written without day part. If day part is omitted than by default it will take 1
<!DOCTYPE html>
<html>
<body>
<span id="date"></span>
<script>
var d = new Date("2016-06");
document.getElementById('date').innerHTML=d;
</script>
</body>
</html>
If month and day part will be omitted, it will take first month and day
<!DOCTYPE html>
<html>
<body>
<span id="date"></span>
<script>
var d = new Date("2016");
document.getElementById('date').innerHTML=d;
</script>
</body>
</html>
Optional Time in HH:MM:SS format can be added to date
<!DOCTYPE html>
<html>
<body>
<span id="date"></span>
<script>
var d = new Date("2016-06-04T21:25:50");
document.getElementById('date').innerHTML=d;
</script>
</body>
</html>
JavaScript long dates can be written in MMM DD YYYY format
<!DOCTYPE html>
<html>
<body>
Month names are case insensitive and comma within date string will be ignored :
<p id="date"></p>
<p id="date1"></p>
<p id="date2"></p>
<p id="date3"></p>
<p id="date4"></p>
<script>
var d = new Date("Jun 04 2016");
var d1 = new Date("04 Jun 2016");
var d2 = new Date("June 04 2016");
var d3 = new Date("04 June 2016");
var d4 = new Date("JANUARY, 25, 2015");
document.getElementById('date').innerHTML=d;
document.getElementById('date1').innerHTML=d1;
document.getElementById('date2').innerHTML=d2;
document.getElementById('date3').innerHTML=d3;
document.getElementById('date4').innerHTML=d4;
</script>
</body>
</html>
Short dates are written in MM/DD/YYYY or YYYY/MM/DD format
<!DOCTYPE html>
<html>
<body>
Short dates can be written in MM/DD/YYYY or YYYY/MM/DD format.
<p id="date"></p>
<p id="date1"></p>
<script>
var d = new Date("06/04/2016");
var d1 = new Date("2016/06/04");
document.getElementById('date').innerHTML=d;
document.getElementById('date1').innerHTML=d1;
</script>
</body>
</html>
JavaScript date object can take full date format as written by date object without any arguments
<!DOCTYPE html>
<html>
<body>
Javascript date object can take full date format
<p id="date"></p>
<script>
var ldate = new Date("Sun Jun 05 2016 00:00:00 GMT+0530 (India Standard Time)");
document.getElementById('date').innerHTML=ldate;
</script>
</body>
</html>
Below timezone are allowed in JavaScript Date object
Time Zone Description UTC Coordinated Universal Time GMT Greenwich Mean Time EDT (US) Eastern Daylight Time CDT (US) Central Daylight Time MDT (US) Mountain Daylight Time PDT (US) Pacific Daylight Time EST (US) Eastern Standard Time CST (US) Central Standard Time MST (US) Mountain Standard Time PST (US) Pacific Standard Time
If timezone is not specified when get/set date object, than it will use browser’s default timezone.