date in javascript

1// these are the most useful ones IMO
2var time = new Date();
3time.getDate(); // returns value 1-31 for day of the month
4time.getDay(); //returns value 0-6 for day of the week
5time.getFullYear(); //returns a 4 digit value for the current year
6time.getHours(); //returns value 0-23 for the current hour
7time.getMinutes(); //returns value 0-59 for the current minute of the hour
8time.getSeconds(); //returns value 0-59 for current second of the minute
9time.getMilliseconds(); //returns value 0-999 for current ms of the second
10time.getTime(); //returns date as ms since Jan 1, 1970
11time.toDateString(); //returns a string (e.g. "Fri May 9 2020")
12time.toLocaleString(); //returns date and time (e.g. "9/12/2015, 6:08:25 PM")
13time.toLocaleTimeString(); //returns time (e.g. "6:08:25 PM")
14time.toLocaleDateString(); //returns date (e.g. "9/12/2015")

1var today = new Date();
2var time = today.getHours() + ":" + today.getMinutes() + ":" + today.getSeconds();
3

1var d= new Date();
2d.getFullYear();	//Get the year as a four digit number (yyyy)
3d.getMonth();	//Get the month as a number (0-11)
4d.getDate();	//Get the day as a number (1-31)
5d.getHours();	//Get the hour (0-23)
6d.getMinutes();	//Get the minute (0-59)
7d.getSeconds();	 //Get the second (0-59)
8d.getMilliseconds()	//Get the millisecond (0-999)
9d.getTime();	//Get the time (milliseconds since January 1, 1970)
10d.getDay();  //Get the weekday as a number (0-6)
11d.Date.now();	//Get the time. ECMAScript 5.
12d.setDate()	//Set the day as a number (1-31)
13d.setFullYear()	//Set the year (optionally month and day)
14d.setHours()	//Set the hour (0-23)
15d.setMilliseconds()	//Set the milliseconds (0-999)
16d.setMinutes()	//Set the minutes (0-59)
17d.setMonth()	//Set the month (0-11)
18d.setSeconds()	//Set the seconds (0-59)
19d.setTime()	//Set the time (milliseconds since January 1, 1970)

1// Several ways to create a Date object
2let today = new Date();
3let birthday = new Date("December 17, 1995 03:24:00");
4let birthday = new Date("1995-12-17T03:24:00");
5let birthday = new Date(1995, 11, 17); // the month is 0-indexed
6let birthday = new Date(1995, 11, 17, 3, 24, 0);
7let birthday = new Date(628021800000); // passing epoch timestamp
8
9// To get Date, Month and Year or Time
10let [month, date, year] = new Date().toLocaleDateString("en-US").split("/");
11let [hour, minute, second] = new Date()
12   .toLocaleTimeString("en-US")
13   .split(/:| /);
14
15// Two digit years map to 1900 – 1999
16let date = new Date(98, 1); // Sun Feb 01 1998 00:00:00 GMT+0000 (GMT)
17// Deprecated method; 98 maps to 1998 here as well
18date.setYear(98); // Sun Feb 01 1998 00:00:00 GMT+0000 (GMT)
19date.setFullYear(98); // Sat Feb 01 0098 00:00:00 GMT+0000 (BST)

1getDate() in javascript only returns the day as number (1-31)
2
3Example
4var d = new Date();
5document.getElementById("demo").innerHTML = d.getDate();
6
7Output:
822
9
10Method	            Description
11getFullYear()	    Get the year as a four digit number (yyyy)
12getMonth()	        Get the month as a number (0-11)
13getDate()	        Get the day as a number (1-31)
14getHours()	        Get the hour (0-23)
15getMinutes()	    Get the minute (0-59)
16getSeconds()	    Get the second (0-59)
17getMilliseconds()	Get the millisecond (0-999)
18getTime()	        Get the time (milliseconds since January 1, 1970)
19getDay()	        Get the weekday as a number (0-6)
20Date.now()	        Get the time. ECMAScript 5.

1var d = new Date();
2
3//1628202691394 miliseconds passed since 1970
4Number(d) 
5Date("2017-06-23");                 // date declaration
6Date("2017");                       // is set to Jan 01
7Date("2017-06-23T12:00:00-09:45");  // date - time YYYY-MM-DDTHH:MM:SSZ
8Date("June 23 2017");               // long date format
9Date("Jun 23 2017 07:45:00 GMT+0100 (Tokyo Time)"); // time zone