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I'm trying to write a statement that says "if time is this and less than that then". I can use get hours and get min. However, I'm having problems combining a time such as 9:30.
Example,
var now = new Date();
var hour = now.getHours();
var day = now.getDay();
var mintues = now.getMinutes();
if (day == 0 && hour >= 9 && hour <= 11 && mintues >= 30) {
document.write(now);
}
This only if the time is less between 9:30 10. As soon as the clock hits 10 the minutes are then < 30 and the script breaks.
Any thoughts on how to better incorporate the time function to make this theory work?
Thanks,
use new Date().getTime() returns milliseconds for much easier comparison. This way there is no need to check hour, min, second, millisecond. Fiddle link
var d930 = new Date(2010, 12, 21, 9, 30, 0, 0), // today 9:30:00:000
d931 = new Date(2010, 12, 21, 9, 31, 0, 0), // today 9:31:00:000
t930 = d930.getTime(),
t931 = d931.getTime();
console.log(t931 > t930);
This way your code can check against a static 9:30 time.
var time930 = new Date(2010, 12, 21, 9, 30, 0, 0).getTime(),
sunday = 0,
now = new Date();
if(now.getDay() == sunday && now.getTime() >= time930){
/* do stuff */
}
You have a few typos and basic javascript errors.
Might wanna brush up on the basics.
W3Schools is where I learned all I know.
It works fine if you fix them...
var now = new Date();
var hour = now.getHours();
var day = now.getDay();
var minutes = now.getMinutes();
if(day == 0 && hour == 9 && minutes < 30 && minutes > 10 || day == 0 && hour == 9)
document.write('Time is between 9:10 and 9:30');
Think of the if statement as basic logic.
If the day is Sunday(0)
AND the hour is 9
AND the minutes are greater than 10
AND the minutes are less than 10
OR the day is Sunday(0)
AND the hour is before 9.
var now = new Date();
var closeTime = new Date();
closeTime.setHours(9); closeTime.setMinutes(30);
console.log(now, closeTime, now.getTime() >= closeTime.getTime());
close time is based on today, then we just change the hours and minutes to 9:30.
I made this solution simple and easy to read (thus easy to adjust).
// we need a function that makes hours and minutes a two digit number
Object.prototype.twoDigits = function () {
return ("0" + this).slice(-2);
}
// get current date and time
let now = new Date();
// compile the current hour and minutes in the format 09:35
timeOfDay = now.getHours().twoDigits() + ':' + now.getMinutes().twoDigits();
// test if timeOfDay is within a given time frame
if ('09:30' <= timeOfDay && timeOfDay <= '11:30') {
console.log('inside time frame');
} else {
console.log('outside time frame');
}
I had a similar problem to solve today, I setup a little component that returns if a place of business is open or not. Got the time by dividing the minutes by 100 then adding it to the hours. So 8:30 is represented as 8.3
let d = new Date()
let day = d.getDay()
let hours = d.getHours()
let minutes = d.getMinutes() / 100
let time = hours + minutes
if (day == 1) {
if (time > 8.3 && time < 17.3) {
setIsOpen(true)
} else {
setIsOpen(false)
}
}
if the hour is less than 9, true
or
if hour is 9 and minutes lt 30, true
so that would look like
if ((hour < 9) || (hour == 9 && minutes < 30))
Use words to figure out your logic. Symbols are just shortcuts.
One way is to do a direct comparison on date objects. Choose an arbitrary year, month and day, and then incorporate your times as follows:
var older = new Date("1980-01-01 12:15");
var newer = new Date("1980-01-01 12:30");
if (newer > older){
alert("Newer time is newer");
} else {
alert ("The time is not newer");
}
The MDC documentation on the Date object will help with some more details. The bottom line is that if you want to compare times, you don't actually need to call any methods on the objects, and it's possible to directly compare them. The date() object can take a variety of strings to assign a new time to the returned instance, these are from the MDC documentation:
today = new Date();
birthday = new Date("December 17, 1995 03:24:00");
birthday = new Date(1995,11,17);
birthday = new Date(1995,11,17,3,24,0);
As you can see, it's pretty simple. Don't complicate, and have a look through the documentation :)
While we're here, here's a test using your example:
var base = new Date("1980-01-01 9:30");
var test = new Date("1980-01-01 9:30:01");
if (test >= base){
alert("test time is newer or equal to base time");
} else {
alert ("test time is older than 9.30");
}
Try this:
var now = new Date();
var hour = now.getHours();
var mintues = now.getMinutes();
if(
(hour*60 + mintues) > 570 &&
hour <= 11
)
{
document.write(now);
}
I don't quite fully understand your question but hope this helps.
c = new Date();
nhour = c.getHours();
nmin = c.getMinutes();
if(nmin <= 9) {
nmin = "0" + nmin;
}
if(nhour <= 9) {
nhour = "0" + nhour;
}
newtime = nhour + "" + nmin;
if(newtime <= 0930){
alert("It is before 9:30am or earlier");
}
I have this javascript code to schedule when certain divs show, but the problem I'm having is it's not using device time or our time zone. I really need it to be assigned to the central time zone.
function displayMsg() {
var currentTime = new Date();
function toUTC(date) {
return Date.UTC(
date.getFullYear(),
date.getMonth(),
date.getDate(),
date.getHours(),
date.getMinutes(),
date.getSeconds(),
date.getMilliseconds()
);
}
toUTC(currentTime);
var startMsg1Time = new Date("2021-10-03T11:15:00Z");
var endMsg1Time = new Date("2021-10-08T14:33:00Z");
var startMsg2Time = new Date("2021-11-15T23:00:01Z");
var endMsg2Time = new Date("2021-11-16T22:59:59Z");
if (currentTime.getTime() > startMsg1Time.getTime() && currentTime.getTime() <= endMsg1Time.getTime()) {
$('.Msg1').show();
} else if (currentTime.getTime() > endMsg1Time.getTime) {
$('.Msg1').hide();
}
if (currentTime.getTime() > startMsg2Time.getTime() && currentTime.getTime() <= endMsg2Time.getTime()) {
$('.Msg2').show();
} else if (currentTime.getTime() > endMsg2Time.getTime) {
$('.Msg2').hide();
}
}
displayMsg();
As a side note, this isn't completely achieving what I need. I'm trying to have a message show every Sunday from 8:30am-11:15am and Friday from 7:00pm-8:15pm. I was going to use this method and just create a schedule a month at a time, but if anyone can recommend a better approach then I'm happy to hear.
You can do something like in below snippet , i.e , giving only minutes and hour and then checking if day = 1 (Monday) . I have set alarm time to 11:25 PM to 11:35 PM(Monday) (You can set any)
Use update of alarm according to need , here I have set 1sec using setInterval
Below snippet is for demo only , you can have any number of messages and alarm and specify day of alarm to come up or month (and can be year to which alarm ring)
setInterval(function() {
var d = new Date();
var Msg1Day = d.getDay();
var Msg1TimeStart = new Date(d.getFullYear(), d.getMonth(), d.getDate(), 23, 25, 0, 0)
var Msg1TimeEnd = new Date(d.getFullYear(), d.getMonth(), d.getDate(), 23, 35, 0, 0)
if (Msg1Day === 1) {
if (d >= Msg1TimeStart && d <= Msg1TimeEnd) {
document.querySelector("#demo").innerHTML = "Alarm is ON"
document.querySelector(".Msg1").innerHTML = "You already enjoyed Sunday, It's Monday Time and soon will Be Tuesday(Alarm is from 11:25 PM - 11:35 PM)"
} else {
document.querySelector("#demo").innerHTML = "Alarm is OFF"
document.querySelector(".Msg1").innerHTML = ""
}
} else {
document.querySelector("#demo").innerHTML = "Today is not monday"
}
}, 1000);
<div class="Msg1"></div>
<div id="demo">Alaram status will be in 1sec and will be updated every second</div>
I need to find this month, previous month and the next month of a specific date.
For example, date was set to 31 of every month, what I expect to get the date is
2018-02-28, 2018-03-31 and 2018-04-30. For those dates which has no 31, than it becomes the day before.
And finally generate 2 period, 2018-02-28 to 2018-03-29, 2018-03-30 to 2018-04-31.
I don't know how to handle feb and the month which less than 31.
var d = new Date();
var tyear = d.getFullYear(); //2018
var tmonth = d.getMonth(); //2
new Date(2018, tmonth-1, 31);//output 2018-03-02 not what I wanted
A simple algorithm is to add months to the original date, and if the new date is wrong, set it to the last day of the previous month. Keeping the original date values unmodified helps, e.g.
/* #param {Date} start - date to start
** #param {number} count - number of months to generate dates for
** #returns {Array} monthly Dates from start for count months
*/
function getMonthlyDates(start, count) {
var result = [];
var temp;
var year = start.getFullYear();
var month = start.getMonth();
var startDay = start.getDate();
for (var i=0; i<count; i++) {
temp = new Date(year, month + i, startDay);
if (temp.getDate() != startDay) temp.setDate(0);
result.push(temp);
}
return result;
}
// Start on 31 Jan in leap year
getMonthlyDates(new Date(2016,0,31), 4).forEach(d => console.log(d.toString()));
// Start on 31 Jan not in leap year
getMonthlyDates(new Date(2018,0,31), 4).forEach(d => console.log(d.toString()));
// Start on 30 Jan
getMonthlyDates(new Date(2018,0,30), 4).forEach(d => console.log(d.toString()));
// Start on 5 Jan
getMonthlyDates(new Date(2018,0,5), 4).forEach(d => console.log(d.toString()));
I think you're going to need an array with 12 numbers in it. Each number is the amount of days in each month and the numbers in the array go in order (first number is 31 because January has 31 days, second is 28 or 29 for Feb), etc. Then you'll get the month number from your input date and look in the array at the number corresponding to the month number +/- 1.
You'll then need to construct a date for the previous month and the next month based on the number of days in the current month.
See comments inline:
let daysInMonths = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
document.getElementById("date").addEventListener("input", function(){
console.clear();
// Create new Date based on value in date picker
var selectedDate = new Date(this.value + 'T00:00');
var year = selectedDate.getYear();
// Determine if it is a leap year (Feb has 29 days) and update array if so.
if (((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0)) {
daysInMonths[1] = 29;
}
var selectedDateMonth = selectedDate.getMonth();
// Get previous month number (if current month is January, get December)
let prevMonth = selectedDateMonth > 0 ? selectedDateMonth - 1 : 11;
let prevMonthDate = null;
// If selected date is last day of month...
if(selectedDate.getDate() === daysInMonths[selectedDateMonth]){
// Create new date that takes the selected date and subtracts the correct amount of
// days from it based on a lookup in the array.
var newDate1 = new Date(selectedDate.getTime());
prevMonthDate =
new Date(newDate1.setDate(selectedDate.getDate() - daysInMonths[selectedDateMonth]));
} else {
// Create a new date that is last month and one day earlier
var newDate2 = new Date(selectedDate.getTime());
prevMonthDate =
new Date(new Date(newDate2.setDate(selectedDate.getDate() - 1))
.setMonth(selectedDate.getMonth() - 1));
}
// Get next month (if current month is December, get January
let nextMonth = selectedDateMonth < 11 ? selectedDateMonth + 1 : 0;
let nextMonthDate = null;
// Same idea for next month, but add instead of subtract.
// If selected date is last day of month...
if(selectedDate.getDate() === daysInMonths[selectedDateMonth]){
var newDate3 = new Date(selectedDate.getTime());
nextMonthDate =
new Date(newDate3.setDate(selectedDate.getDate() + daysInMonths[selectedDateMonth + 1]));
} else {
var newDate4 = new Date(selectedDate.getTime());
nextMonthDate = new Date(new Date(newDate4.setDate(selectedDate.getDate() + 1)).setMonth(selectedDate.getMonth() + 1));
}
console.log("Last month date: " + prevMonthDate.toLocaleDateString());
console.log("Next month date: " + nextMonthDate.toLocaleDateString());
});
<p>Pick a date: <input type="date" id="date"></p>
Use this approach:
Javascript Date Object – Adding and Subtracting Months
From the Author
There is a slight problem with the Javascript Date() Object when trying to advance to the next month or go back to the previous month.
For example, if your date is set to October 31, 2018 and you add one month, you'd probably expect the new date to be November 30, 2018 because November 31st doesn't exist. This, however, isn't the case.
Javascript automatically advances your Date object to December 1st. This functionality is very useful in most situations(i.e. adding days to a date, determining the number of days in a month or if it's a leap year), but not for adding/subtracting months. I've put together some functions below that extend the Date() object: nextMonth() and prevMonth().
function prevMonth() {
var thisMonth = this.getMonth();
this.setMonth(thisMonth - 1);
if (this.getMonth() != thisMonth - 1 && (this.getMonth() != 11 || (thisMonth == 11 && this.getDate() == 1)))
this.setDate(0);
}
function nextMonth() {
var thisMonth = this.getMonth();
this.setMonth(thisMonth + 1);
if (this.getMonth() != thisMonth + 1 && this.getMonth() != 0)
this.setDate(0);
}
Date.prototype.nextMonth = nextMonth;
Date.prototype.prevMonth = prevMonth;
var today = new Date(2018, 2, 31); //<----- March 31st, 2018
var prevMonth = new Date(today.getTime());
prevMonth.prevMonth();
console.log("Previous month:", prevMonth);
console.log("This month:", today)
var nextMonth = new Date(today.getTime());
nextMonth.nextMonth();
console.log("Next month:", nextMonth);
.as-console-wrapper { max-height: 100% !important; top: 0; }
Dates and time zones are a real pain in JS, so challenge accepted.
I broke it down in two steps:
- Count the days of prev and next month
- Compare with selected day and pick the lowest number
Testcases included
function createUTCDate(year, month, day) {
return new Date(Date.UTC(year, month, day));
}
function splitDate(date) {
return {
year: date.getUTCFullYear(),
month: date.getUTCMonth(),
day: date.getUTCDate()
};
}
function numberOfDaysInMonth(year, month) {
return new Date(year, month + 1, 0).getDate();
}
function dateNextMonth(dateObj) {
const daysNextMonth = numberOfDaysInMonth(dateObj.year, dateObj.month + 1);
const day = Math.min(daysNextMonth, dateObj.day);
return createUTCDate(dateObj.year, dateObj.month + 1, day);
}
function datePreviousMonth(dateObj) {
const daysPrevMonth = numberOfDaysInMonth(dateObj.year, dateObj.month - 1);
const day = Math.min(daysPrevMonth, dateObj.day);
return createUTCDate(dateObj.year, dateObj.month - 1, day);
}
const log = console.log;
function print(dateString) {
const date = new Date(dateString);
const dateObj = splitDate(date);
log("Previous: ", datePreviousMonth(dateObj).toISOString());
log("Selected: ", date.toISOString());
log("Next: ", dateNextMonth(dateObj).toISOString());
log("--------------");
}
const testCases = [
"2018-03-01 UTC",
"2018-03-31 UTC",
"2018-01-01 UTC",
"2018-12-31 UTC"
];
testCases.forEach(print);
Please note that the hack with new Date(xxx + " UTC") is not according to spec and is just there for testing purposes. Results may vary per browser.
You should choose an input format and construct your dates accordingly.
I handle it in a foolish way by concatenating string
let daysInMonths = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
let months = ["01", "02", "03", "04", "05", "06", "07", "08", "09", "10", "11", "12"];
var target = nexttarget = lasttarget = "29"; //target day
if (((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0)) {
daysInMonths[1] = 29;
}
function findLastDay(target, month){
if(target > daysInMonths[month]){
target = daysInMonths[month];
}
return target;
}
then
var d = new Date();
var year = d.getFullYear();
var month = d.getMonth();
target = findLastDay(target, month);
var this_month = year+"-"+months[month]+"-"+target;
console.log(this_month);//2018-03-29
// next month
if(month == 11){
nextmonth = 0;
nextyear = year + 1;
}else{
nextmonth = month+1;
nextyear = year;
}
nexttarget = findLastDay(nexttarget, nextmonth);
var next_month = nextyear+"-"+months[nextmonth]+"-"+nexttarget;
console.log(next_month);//2018-04-29
//last month
if(month == 0){
lastmonth = 11;
lastyear = year - 1;
}else{
lastmonth = month - 1;
lastyear = year;
}
lasttarget = findLastDay(lasttarget, lastmonth);
var last_month = lastyear+"-"+months[lastmonth]+"-"+lasttarget;
console.log(last_month);//2018-02-28
Date handling is tricky at the best of times. Don't do this yourself. Use Moment.js.
var target = 31;
var today = moment().date(target).calendar();
// today == '03/31/2018'
var nextMonth = moment().date(target).add(1, 'month').calendar();
// nextMonth == '04/30/2018'
var lastMonth = moment().date(target).subtract(1, 'month').calendar()
// lastMonth == '02/28/2018'
This question already has answers here:
Get week of year in JavaScript like in PHP
(23 answers)
Closed 5 years ago.
I'm looking for a tested solid solution for getting current week of the year for specified date. All I can find are the ones that doesn't take in account leap years or just plain wrong. Does anyone have this type of stuff?
Or even better a function that says how many weeks does month occupy. It is usually 5, but can be 4 (feb) or 6 (1st is sunday and month has 30-31 days in it)
=================
UPDATE:
Still not sure about getting week #, but since I figured out it won't solve my problem with calculating how many weeks month occupy, I abandoned it.
Here's a function to find out how many weeks exactly month occupy on the calendar:
getWeeksNum: function(year, month) {
var daysNum = 32 - new Date(year, month, 32).getDate(),
fDayO = new Date(year, month, 1).getDay(),
fDay = fDayO ? (fDayO - 1) : 6,
weeksNum = Math.ceil((daysNum + fDay) / 7);
return weeksNum;
}
/**
* Returns the week number for this date. dowOffset is the day of week the week
* "starts" on for your locale - it can be from 0 to 6. If dowOffset is 1 (Monday),
* the week returned is the ISO 8601 week number.
* #param int dowOffset
* #return int
*/
Date.prototype.getWeek = function (dowOffset) {
/*getWeek() was developed by Nick Baicoianu at MeanFreePath: http://www.meanfreepath.com */
dowOffset = typeof(dowOffset) == 'number' ? dowOffset : 0; //default dowOffset to zero
var newYear = new Date(this.getFullYear(),0,1);
var day = newYear.getDay() - dowOffset; //the day of week the year begins on
day = (day >= 0 ? day : day + 7);
var daynum = Math.floor((this.getTime() - newYear.getTime() -
(this.getTimezoneOffset()-newYear.getTimezoneOffset())*60000)/86400000) + 1;
var weeknum;
//if the year starts before the middle of a week
if(day < 4) {
weeknum = Math.floor((daynum+day-1)/7) + 1;
if(weeknum > 52) {
nYear = new Date(this.getFullYear() + 1,0,1);
nday = nYear.getDay() - dowOffset;
nday = nday >= 0 ? nday : nday + 7;
/*if the next year starts before the middle of
the week, it is week #1 of that year*/
weeknum = nday < 4 ? 1 : 53;
}
}
else {
weeknum = Math.floor((daynum+day-1)/7);
}
return weeknum;
};
Usage:
var mydate = new Date(2011,2,3); // month number starts from 0
// or like this
var mydate = new Date('March 3, 2011');
alert(mydate.getWeek());
Source
For those looking for a more simple approach;
Date.prototype.getWeek = function() {
var onejan = new Date(this.getFullYear(),0,1);
var today = new Date(this.getFullYear(),this.getMonth(),this.getDate());
var dayOfYear = ((today - onejan + 86400000)/86400000);
return Math.ceil(dayOfYear/7)
};
Use with:
var today = new Date();
var currentWeekNumber = today.getWeek();
console.log(currentWeekNumber);
Consider using my implementation of "Date.prototype.getWeek", think is more accurate than the others i have seen here :)
Date.prototype.getWeek = function(){
// We have to compare against the first monday of the year not the 01/01
// 60*60*24*1000 = 86400000
// 'onejan_next_monday_time' reffers to the miliseconds of the next monday after 01/01
var day_miliseconds = 86400000,
onejan = new Date(this.getFullYear(),0,1,0,0,0),
onejan_day = (onejan.getDay()==0) ? 7 : onejan.getDay(),
days_for_next_monday = (8-onejan_day),
onejan_next_monday_time = onejan.getTime() + (days_for_next_monday * day_miliseconds),
// If one jan is not a monday, get the first monday of the year
first_monday_year_time = (onejan_day>1) ? onejan_next_monday_time : onejan.getTime(),
this_date = new Date(this.getFullYear(), this.getMonth(),this.getDate(),0,0,0),// This at 00:00:00
this_time = this_date.getTime(),
days_from_first_monday = Math.round(((this_time - first_monday_year_time) / day_miliseconds));
var first_monday_year = new Date(first_monday_year_time);
// We add 1 to "days_from_first_monday" because if "days_from_first_monday" is *7,
// then 7/7 = 1, and as we are 7 days from first monday,
// we should be in week number 2 instead of week number 1 (7/7=1)
// We consider week number as 52 when "days_from_first_monday" is lower than 0,
// that means the actual week started before the first monday so that means we are on the firsts
// days of the year (ex: we are on Friday 01/01, then "days_from_first_monday"=-3,
// so friday 01/01 is part of week number 52 from past year)
// "days_from_first_monday<=364" because (364+1)/7 == 52, if we are on day 365, then (365+1)/7 >= 52 (Math.ceil(366/7)=53) and thats wrong
return (days_from_first_monday>=0 && days_from_first_monday<364) ? Math.ceil((days_from_first_monday+1)/7) : 52;
}
You can check my public repo here https://bitbucket.org/agustinhaller/date.getweek (Tests included)
Get week number
Date.prototype.getWeek = function() {
var dt = new Date(this.getFullYear(),0,1);
return Math.ceil((((this - dt) / 86400000) + dt.getDay()+1)/7);
};
var myDate = new Date(2013, 3, 25); // 2013, 25 April
console.log(myDate.getWeek());
I know this is an old question, but maybe it helps:
http://weeknumber.net/how-to/javascript
// This script is released to the public domain and may be used, modified and
// distributed without restrictions. Attribution not necessary but appreciated.
// Source: https://weeknumber.net/how-to/javascript
// Returns the ISO week of the date.
Date.prototype.getWeek = function() {
var date = new Date(this.getTime());
date.setHours(0, 0, 0, 0);
// Thursday in current week decides the year.
date.setDate(date.getDate() + 3 - (date.getDay() + 6) % 7);
// January 4 is always in week 1.
var week1 = new Date(date.getFullYear(), 0, 4);
// Adjust to Thursday in week 1 and count number of weeks from date to week1.
return 1 + Math.round(((date.getTime() - week1.getTime()) / 86400000
- 3 + (week1.getDay() + 6) % 7) / 7);
}
// Returns the four-digit year corresponding to the ISO week of the date.
Date.prototype.getWeekYear = function() {
var date = new Date(this.getTime());
date.setDate(date.getDate() + 3 - (date.getDay() + 6) % 7);
return date.getFullYear();
}
/*get the week number by following the norms of ISO 8601*/
function getWeek(dt){
var calc=function(o){
if(o.dtmin.getDay()!=1){
if(o.dtmin.getDay()<=4 && o.dtmin.getDay()!=0)o.w+=1;
o.dtmin.setDate((o.dtmin.getDay()==0)? 2 : 1+(7-o.dtmin.getDay())+1);
}
o.w+=Math.ceil((((o.dtmax.getTime()-o.dtmin.getTime())/(24*60*60*1000))+1)/7);
},getNbDaysInAMonth=function(year,month){
var nbdays=31;
for(var i=0;i<=3;i++){
nbdays=nbdays-i;
if((dtInst=new Date(year,month-1,nbdays)) && dtInst.getDate()==nbdays && (dtInst.getMonth()+1)==month && dtInst.getFullYear()==year)
break;
}
return nbdays;
};
if(dt.getMonth()+1==1 && dt.getDate()>=1 && dt.getDate()<=3 && (dt.getDay()>=5 || dt.getDay()==0)){
var pyData={"dtmin":new Date(dt.getFullYear()-1,0,1,0,0,0,0),"dtmax":new Date(dt.getFullYear()-1,11,getNbDaysInAMonth(dt.getFullYear()-1,12),0,0,0,0),"w":0};
calc(pyData);
return pyData.w;
}else{
var ayData={"dtmin":new Date(dt.getFullYear(),0,1,0,0,0,0),"dtmax":new Date(dt.getFullYear(),dt.getMonth(),dt.getDate(),0,0,0,0),"w":0},
nd12m=getNbDaysInAMonth(dt.getFullYear(),12);
if(dt.getMonth()==12 && dt.getDay()!=0 && dt.getDay()<=3 && nd12m-dt.getDate()<=3-dt.getDay())ayData.w=1;else calc(ayData);
return ayData.w;
}
}
alert(getWeek(new Date(2017,01-1,01)));
I need Javascript code for a website to automatically adjust a date. The goal is to have the code automatically adjust the following statement to be the second Saturday of every month from now until eternity:
Next membership meeting: Saturday, MONTH, DAY, YEAR 11 a.m. to noon.
Anyone have an idea? Much appreciated!
This function will get you the date object, you can pull out what you need from it:
var getMeeting = function(year, month){
var date = new Date(year, month, 1, 0, 0, 0, 0);
date.setDate(14-date.getDay());
return date;
};
alert(getMeeting(2011,5));
I didn't test but here is the basics:
//our main code
var Months = ["Jan", "Feb", "Mar", /*... you finish... */ ];
var meetingDate = getMonthlyMeeting();
document.Write( "<i>Next membership meeting:</i> Saturday, " + Months[meetingDate.getMonth()] + ", " + meetingDate.getDay() + ", " + meetingDate.getYear() + " 11 a.m. to noon.");
// call this to get the monthly meeting date
// returns a Date() object
function getMonthlyMeeting(){
var today = new Date(); //JS automatically initializes new Date()s to the current time
//first, see if today is our meeting day
var meetingDate;
var thisMonthsMeeting = getSecondTuesdayInMonth(today.getMonth(), today.getYear());
if( thisMonthsMeeting.getDay() == today.getDay() ){
// today is our meeting day!
meetingDate = today;
}
else {
if ( today.getDay() < thisMonthsMeeting.getDay() ){
// it hasn't happened this month yet
meetingDate = thisMonthsMeeting;
} else {
//this month's meeting day has already passed
if( today.getMonth() == 11 ){
// rolling over to the next year
meetingDate = getSecondTuesdayInMonth(0, today.getYear() + 1);
} else {
meetingDate = getSecondTuesdayInMonth(today.getMonth() + 1, today.getYear());
}
}
}
return meetingDate;
}
// this is a helper function to get the second tuesday in any month
// returns a Date() object
function getSecondTuesdayInMonth(var month, var year){
var saturdays = 0;
var testDay= new Date();
while( testDay.getDay() != 2 && saturdays < 2 ){
//while the day we are testing isnt tuesday (2) and we haven't found it twice
if( testDay.getDay() == 2 )
saturdays = saturdays + 1; //we found a saturday
testDay= new Date(testDay.getTime() + 86400000); //increment our day to the next day
}
//when we finish the while loop, we are on our day
return testDay;
}
So, I figure that the meat of your problem is: How do I know what the second saturday of each month is?
Not tested, but this is what I came up with:
It is abstracted for any nth day of any month.
nthDate = function(nth_week, nth_day, month){
var src_date = new Date();
src_date.setDate(1);
src_date.setMonth(month);
return ( (nth_week * 7) - src_date.getDay() ) - ( Math.abs( nth_day - 6) );
};
var cur_date = new Date();
var cur_day = cur_date.getDay();
//2 for the 2nd week of the month
//6 is the integer value for saturday (days of the week 0-6)
var nth_date = nthDate( 2, 6, cur_date.getMonth() );
if(cur_day < nth_date){
//display the upcoming date here
}else if( cur_day > nth_date){
//figure out next month's date and display that
var next_date = nthDate(2, 6, (cur_date.getMonth() +1) );
//does this deal with the case of the month being december?? not sure.
}
The 2nd week is in the range of 14 days into the month.
We can:
first subtract the offset for the day of the week that this month starts with,
then second:
we can subtract the offset for the day of the week that we are looking for.
(this needs to be the offset of days, so saturday is a 0 (zero) offset. We get this value from the absolute value of nth day minus the number of days in the week.
This gives us the date of the second saturday.
Then, because you have some ints you can do a simple compare against the values.
If we're before the second saturday, display that, if not calculate a new date for next month.
Hope that helps.