Working with dates in javascript

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To create date object in JavaScript use Date() constructor

The following example writes the current Date and Time to the web page
document.write(new Date());

If the Date() constructor is used without any arguments, it returns the current date and time. To create a date object with specific dates there are 2 ways.

Creating a specific date object in JavaScript using a date string
var dateOfBirth = new Date(“January 13, 1980 11:20:00”);
document.write(dateOfBirth);

You can also create a specific date object using number for year, month, day, hours, minutes, seconds, & milliseconds. The syntax is shown below.
var dateOfBirth = new Date(year, month, day, hours, minutes, seconds, milliseconds);

Example :
var dateOfBirth = new Date(1980, 0, 13, 11, 20, 0, 0);
document.write(dateOfBirth);

Please note : In JavaScript month numbers start from ZERO. So if you want the month of march then use 2 instead of 3.

The above code produces the following output on my machine, because I have (UTC) Dublin, Edinburgh, Lisbon, London time zone selected on my machine
Sun Jan 13 1980 11:20:00 GMT+0000 (GMT Standard Time)

If you have a different time zone selected on your computer, you may get a slightly different result. For example if you have (UTC+05:30) Chennai, Kolkata, Mumbai, New Delhi time zone selected, the result will be as shown below
Sun Jan 13 1980 11:20:00 GMT+0530 (India Standard Time)

Some useful Date object methods in JavaScript
getFullYear() – Returns the full year (all the four digits)

Example : The following example returns 1980
var year = new Date(1980, 0, 13, 11, 20, 0, 0).getFullYear();
document.write(year);

getMonth() – Returns the month number (from 0-11)

Example : The following example returns 0 (for January)
var month = new Date(1980, 0, 13, 11, 20, 0, 0).getMonth();
document.write(month);

You can use the following code to get the month name from the month number in Javascript. The following example returns January.
function getMonthNameFromNumber(monthNumber)
{
var monthNames = [“January”, “February”, “March”, “April”,
“May”, “June”, “July”, “August”, “September”,
“October”, “November”, “December”];
return monthNames[monthNumber];
}

var monthName = getMonthNameFromNumber(new Date(1980, 0, 13, 11, 20, 0, 0).getMonth());
document.write(monthName);

getDate() – Returns the day of the month (from 1-31)

Example : The following example returns 13
var dayOfMonth = new Date(1980, 0, 13, 11, 20, 0, 0).getDate();
document.write(dayOfMonth);

getDay() – Returns the day number of the week (from 0-6). 0 is sunday, 1 is monday and so on.

Example : The following example returns 0
var dayOfWeek = new Date(1980, 0, 13, 11, 20, 0, 0).getDay();
document.write(dayOfWeek);

You can use the following code to get the day of the week from the day number in Javascript. The following example returns Sunday.
function getWeekDayNameFromNumber(dayNumber)
{
var weekDays = [“Sunday”, “Monday”, “Tuesday”, “Wednesday”, “Thursday”, “Friday”, “Saturday”];
return weekDays[dayNumber];
}

var weekdayName = getWeekDayNameFromNumber(new Date(1980, 0, 13, 11, 20, 0, 0).getDay());
document.write(weekdayName);

You also have the following methods that return the time parts of the date object
getHours() – Returns the hour (from 0-23)
getMinutes() – Returns the minutes (from 0-59)
getSeconds() – Returns the seconds (from 0-59)
getMilliseconds() – Returns the milliseconds (from 0-999)

How to convert date in javascript to dd/mm/yyyy format
function formatDate(date)
{
var day = date.getDate();
if (day [ 10)
{
day = “0” + day;
}

var month = date.getMonth() + 1;
if (month [ 10)
{
month = “0” + month;
}

var year = date.getFullYear();

return day + “/” + month + “/” + year;
}

document.write(formatDate(new Date()));

If you don’t want ZERO (0) before a single digit month or day number, then modify the formatDate() function as shown below.
function formatDate(date)
{
var day = date.getDate();
var month = date.getMonth() + 1;
var year = date.getFullYear();

return day + “/” + month + “/” + year;
}

document.write(formatDate(new Date()));

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