My data looks like this:
[{ x="2013-06-01", y=3}, { x="2013-07-01", y=7 }, { x="2013-08-01", y=3 }]
Chart x-axis is formatted as so:
chart.xAxis
.axisLabel('Date')
.tickFormat(function(d) { return d3.time.format('%b %Y')(new Date(d)); })
;
%b returns May, Jun, July respectively for the dates 2013-06-01, 2013-07-01, 2013-08-01
Why is it returning the previous month, and how can I fix it?
EDIT: If the date is formatted as 2013-06-02, it will return the correct month... does someone know what is happening to cause this?
#Amelia is correct it's because of timezone difference and because Date defaults to 24:00:00 if you don't specify a time. So, in case of EDT, which is -4:00, you lose 4 hours which puts you in the previous day (May 31 2013 20:00:00) and because the days in your dates are 01, this puts you in the previous month.
To bypass this you could append a time to your date if that is allowable in your case.
chart.xAxis
.axisLabel('Date')
.tickFormat(function(d) {
d = d.split('-')
// Create new date by using new Date(year, month, day, hour, second, ms)
// Subtracting 1 is necessary since Javascript months are 0 - 11.
return d3.time.format('%b %Y')(new Date(d[0], +d[1] - 1, d[2], 12, 0, 0));
});
Here is a working Fiddle
Related
As per MDN
"Date objects are based on a time value that is the number of milliseconds since 1 January, 1970 UTC."
Then why does it accept negative values ?
Even if it did shouldn't negative value mean values before Jan 1, 1970 ?
new Date('0000', '00', '-1'); // "1899-12-30T05:00:00.000Z"
new Date('0000', '00', '00'); // "1899-12-31T05:00:00.000Z"
new Date('-9999', '99', '99'); // "-009991-07-08T04:00:00.000Z"
What is happening ?
Update
For some positive values , the year begins from 1900
new Date(100); // "1970-01-01T00:00:00.100Z" // it says 100Z
new Date(0100); // "1970-01-01T00:00:00.064Z" // it says 64Z
new Date("0006","06","06"); // "1906-07-06T04:00:00.000Z"
Also note that, in the last one, the date is shown as 4 which is wrong.
I suspect this is some sort of Y2K bug ?!!
This is hard and inconsistent, yes. The JavaScript Date object was based on the one in Java 1.0, which is so bad that Java redesigned a whole new package.
JavaScript is not so lucky.
Date is "based on" unix epoch because of how it is defined. It's internal details.
1st Jan 1970 is the actual time of this baseline.
since is the direction of the timestamp value: forward for +ve, backward for -ve.
Externally, the Date constructor has several different usages, based on parameters:
Zero parameters = current time
new Date() // Current datetime. Every tutorial should teach this.
The time is absolute, but 'displayed' timezone may be UTC or local.
For simplicity, this answer will use only UTC. Keep timezone in mind when you test.
One numeric parameter = timestamp # 1970
new Date(0) // 0ms from 1970-01-01T00:00:00Z.
new Date(100) // 100ms from 1970 baseline.
new Date(-10) // -10ms from 1970 baseline.
One string parameter = iso date string
new Date('000') // Short years are invalid, need at least four digits.
new Date('0000') // 0000-01-01. Valid because there are four digits.
new Date('1900') // 1900-01-01.
new Date('1900-01-01') // Same as above.
new Date('1900-01-01T00:00:00') // Same as above.
new Date('-000001') // 2 BC, see below. Yes you need all those zeros.
Two or more parameters = year, month, and so on # 1900 or 0000
new Date(0,0) // 1900-01-01T00:00:00Z.
new Date(0,0,1) // Same as above. Date is 1 based.
new Date(0,0,0) // 1 day before 1900 = 1899-12-31.
new Date(0,-1) // 1 month before 1900 = 1899-12-01.
new Date(0,-1,0) // 1 month and 1 day before 1900 = 1899-11-30.
new Date(0,-1,-1) // 1 month and *2* days before 1900 = 1899-11-29.
new Date('0','1') // 1900-02-01. Two+ params always cast to year and month.
new Date(100,0) // 0100-01-01. Year > 99 use year 0 not 1900.
new Date(1900,0) // 1900-01-01. Same as new Date(0,0). So intuitive!
Negative year = BC
new Date(-1,0) // 1 year before 0000-01-01 = 1 year before 1 BC = 2 BC.
new Date(-1,0,-1) // 2 days before 2 BC. Fun, yes? I'll leave this as an exercise.
There is no 0 AC. There is 1 AC and the year before it is 1 BC. Year 0 is 1 BC by convention.
2 BC is displayed as year "-000001".
The extra zeros are required because it is outside normal range (0000 to 9999).
If you new Date(12345,0) you will get "+012345-01-01", too.
Of course, the Gregorian calendar, adopted as late as 1923 in Europe, will cease to be meaningful long before we reach BC.
In fact, scholars accept that Jesus wasn't born in 1 BC.
But with the stars and the land moving at this scale, calendar is the least of your worries.
The remaining given code are just variations of these cases. For example:
new Date(0100) // One number = epoch. 0100 (octal) = 64ms since 1970
new Date('0100') // One string = iso = 0100-01-01.
new Date(-9999, 99, 99) // 9999 years before BC 1 and then add 99 months and 98 days
Hope you had some fun time. Please don't forget to vote up. :)
To stay sane, keep all dates in ISO 8601 and use the string constructor.
And if you need to handle timezone, keep all datetimes in UTC.
Well, firstly, you're passing in string instead of an integer, so that might have something to do with your issues here.
Check this out, it explains negative dates quite nicely, and there is an explanation for your exact example.
Then why does it accept negative values ?
You are confusing the description of how the data is stored internally with the arguments that the constructor function takes.
Even if it did shouldn't negative value mean values before Jan 1, 1970 ?
No, for the above reason. Nothing stops the year, month or day from being negative. You just end up adding a negative number to something.
Also note that, in the last one, the date is shown as 4 which is wrong.
Numbers which start with a 0 are expressed in octal, not decimal. 0100 === 64.
Please have a look at the documentation
Year: Values from 0 to 99 map to the years 1900 to 1999
1970 with appropriate timezone: new Date(0); // int MS since 1970
1900 (or 1899 with applied timezone): new Date(0,0) or new Date(0,0,1) - date is 1 based, month and year are 0 based
1899: new Date(0,0,-1)
I have the following code
String test = "21/04/2013";
fmt = DateTimeFormat.getFormat("MM/dd/yyyy");
Date dateTest = fmt.parse(test);
Window.alert(fmt.format(dateTest));
And the alert box shows the date
09/04/2014
instead of
21/04/2013
Why?
As others already say, it's because of your pattern. What they don't say is why it behaves that way.
When parsing 21/04/2013 as MM/dd/yyyy, DateTimeFormat will decompose the date as:
Month Day of month Year
21 4 2013
and it'll then adjust things to make a valid date. To do that, the Month part is truncated at 12 (so that temporary date is Dec 4th, 2013) and the remainder (21 - 12 = 9) is then added, leading to Sept. 4th 2014, which according to your format displays as 09/04/2014.
You wanted to show 21/04/2013 but the format was MM/dd/yyyy.
It should be dd/MM/yyyy
So change it like this:
String test = "21/04/2013";
fmt = DateTimeFormat.getFormat("dd/MM/yyyy");
Date dateTest = fmt.parse(test);
Window.alert(fmt.format(dateTest));
You're reversing day and month.
String test = "21/04/2013";
fmt = DateTimeFormat.getFormat("dd/MM/yyyy");
Date dateTest = fmt.parse(test);
Window.alert(fmt.format(dateTest));
I have the Drop down with values as "One year ", "Two year",...etc.. Ok? also i have two ajax textbox with calender extender . I want to popup alert message if dropdown selected value is "One year" and duration between the both textbox value Means dates not matches. getting what i mean ? please help me.
Algorithm :
1.Get the both date from the text box.
2. The find the epcoch time for each date. //
3. subtract the both dates.
4. subtract_result = 365*24*60*60 // Finding the 1 year timestamp values
5. So, it the difference exceed than above calculation , you could sure that the date is mis matching.
// This is for first date
first = new Date(2010, 03, 08, 15, 30, 10); // Get the first date epoch object
// document.write((first.getTime())/1000); // get the actual epoch values
second = new Date(2012, 03, 08, 15, 30, 10); // Get the first date epoch object
//document.write((second.getTime())/1000); // get the actual epoch values
diff= second - first ;
one_day_epoch = 24*60*60 ; // calculating one epoch
if ( diff/ one_day_epoch > 365 ) // check , is it exceei
{
alert( 'date is exceeding one year');
}
Hi I have the Drop down with values as "One year ", "Two year",...etc.. Ok? also i have two ajax textbox with calender extender . I want to popup alert message if dropdown selected value is "One year" and duration between the both textbox value Means dates not matches. getting what i mean ? please help me.
How can i get this scenario in javascript ??
Algorithm :
1.Get the both date from the text box.
2. The find the epcoch time for each date. //
3. subtract the both dates.
4. subtract_result = 365*24*60*60 // Finding the 1 year timestamp values
5. So, it the difference exceed than above calculation , you could sure that the date is mis matching.
Javascript:
// This is for first date
first = new Date(2010, 03, 08, 15, 30, 10); // Get the first date epoch object
document.write((first.getTime())/1000); // get the actual epoch values
second = new Date(2012, 03, 08, 15, 30, 10); // Get the first date epoch object
document.write((second.getTime())/1000); // get the actual epoch values
diff= second - first ;
one_day_epoch = 24*60*60 ; // calculating one epoch
if ( diff/ one_day_epoch > 365 ) // check , is it exceei
{
alert( 'date is exceeding one year');
}
I would like to check if a given date is the first, second, third, fourth or last monday, tuesday, wednesday,..., sunday in the dates month.
The function should look like this:
if(checkdate(date, "second", "monday"))
{
alert("This is the second monday of the month");
}
else
{
alert("This is NOT the second monday of the month");
}
I would rather write a function that returns an object telling me the day and the week-number-in-month of the given date. Something like:
function infoDate(date) {
return {
day: date.getDay()+1,
week: (date.getDate()-1)%7+1
}
}
Then I can read the returned object and find out if it's the second monday or whatever:
var info = infoDate(date);
if(info.day==1 && info.week==2) {
// second monday
}
Of course, you can still write another localized function that does exactly what you ask for based on an array of numeral and day names.
use getDate() to get day of the month
then getDay() to get the day of the week
using these two you should be able to accomplish your task. Refer to this http://www.w3schools.com/jsref/jsref_obj_date.asp
It seems to me you only need to divide the date by 7 to know how many full weeks have passed, no matter what day it is. Subtracting one before dividing and adding it after sets the first week from 0 to one.
Date.prototype.weekofMonth= function(){
return Math.floor((this.getDate()-1)/7)+1;
}
alert(new Date().weekofMonth())