We Keep Coding

Javascript Countdown timer does not work

I came across this codepen https://codepen.io/donovanh/pen/JWdyEm, and I was trying to apply it to an older countdown timer I did because this one seemed better.. If I set the countdown date to today then it still says there is 30 days left.
Here is the code where it calculates the difference between dates.
function daysBetween( date1, date2 ) {
//Get 1 day in milliseconds
var one_day=1000*60*60*24;
// Convert both dates to milliseconds
var date1_ms = date1.getTime();
var date2_ms = date2.getTime();
// Calculate the difference in milliseconds
var difference_ms = date2_ms - date1_ms;
// Convert back to days and return
return Math.round(difference_ms/one_day);
}
console.log("Days to end of April = " +
daysBetween(new Date(), new Date("2018-04-30")));
I cannot figure out where the extra days are coming from, any help would be appreciated, thanks

I think that your problem comes from giving wrong month number as argument to Date.UTC. According to docs https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/UTC, month is a 0-11 number. If you would like to call function for todays date, you have to call it like new Date(2018, 3, 10, 12, 15).

Months start from 0 and go to 11.
The end of April is Date("2018-03-30"), not Date("2018-04-30") that is why you get extra 30 or 31 days

How to subtract 2 times with moment.js, then subtract some minutes

I need to subtract 2 times with moment.js (get the difference), and then with that result, subtract some additional minutes (simple int). It's for calculating timesheets. A few examples:
Example #1:
Start time: 10:00 AM (represented in js as "10:00")
End time: 2:00 PM (represented in js as "14:00")
Lunch: 30 minutes ("30")
Expected result: "3:30" (10am - 2pm is 4 hours, minus 30 minutes for lunch = 3hrs 30 mins -- and I need it output as "3:30")
Example #2:
Start time: 6:15 AM (represented in js as "6:15")
End time: 4:45 PM (represented in js as "16:45")
Lunch: 0 minutes ("0")
Expected result: "10:30"
I know moment.js can do this but I'm struggling to get expected results. I've been trying this:
function getTimeInterval(startTime, endTime){
return moment(moment(startTime,"hh:mm").diff(moment(endTime,"hh:mm"))).format("hh:mm");
}
The formatting seems right, but I'm getting incorrect values. For example, the result returned for my example #2 is "6:30" instead of "10:30" And then how do I subtract off int minutes for lunch?
Any help is much appreciated.

// parse time using 24-hour clock and use UTC to prevent DST issues
var start = moment.utc(startTime, "HH:mm");
var end = moment.utc(endTime, "HH:mm");
// account for crossing over to midnight the next day
if (end.isBefore(start)) end.add(1, 'day');
// calculate the duration
var d = moment.duration(end.diff(start));
// subtract the lunch break
d.subtract(30, 'minutes');
// format a string result
var s = moment.utc(+d).format('H:mm');
Pay close attention to the casing of the formats. You were using hh which is for a 12-hour clock.
See also: Get the time difference between two datetimes

You can use the diff method to calculate the difference between two dates and the subtract method to subtract time. In your case:
function getTimeInterval(startTime, endTime, lunchTime){
var start = moment(startTime, "HH:mm");
var end = moment(endTime, "HH:mm");
var minutes = end.diff(start, 'minutes');
var interval = moment().hour(0).minute(minutes);
interval.subtract(lunchTime, 'minutes');
return interval.format("HH:mm");
}

javascript wrong date / days calculation

I need to calculate the number of nights between 2 dates, it works but it's very odd.
If I pick dates like 22,06,2015 and 22,07,2015 it shows me 31 nights, which is wrong since June has only 30 days.
if I pick dates like 01,07,2015 and 31,07,2015 it shows me 30 nights, which is correct.
if I pick dates like 01,07,2015 and 1,08,2015 it shows me 31 nights etc.
if I pick dates like 30,09,2015 and 30,10,2015 it shows me 31.041666666666668 nights which is odd and incorrect.
Hope you can help me with this one. Here's the code:
var date11 = $("#in").val();
var date22 = $("#out").val();
// First we split the values to arrays date1[0] is the year, [1] the month and [2] the day
date111 = date11.split('-');
date222 = date22.split('-');
// Now we convert the array to a Date object, which has several helpful methods
date1 = new Date(date111[2], date111[1], date111[0]);
date2 = new Date(date222[2], date222[1], date222[0]);
// We use the getTime() method and get the unixtime (in milliseconds, but we want seconds, therefore we divide it through 1000)
date1_unixtime = parseInt(date1.getTime() / 1000);
date2_unixtime = parseInt(date2.getTime() / 1000);
// This is the calculated difference in seconds
var timeDifference = date2_unixtime - date1_unixtime;
// in Hours
var timeDifferenceInHours = timeDifference / 60 / 60;
// and finaly, in days :)
var timeDifferenceInDays = timeDifferenceInHours / 24;
Thanks a million!

You aren't subtracting 1 from the calendar month number:
date1 = new Date(date111[2], date111[1] - 1, date111[0]);
--------^^^^
Months are zero indexed. you should probably also round the result as if you cross a daylight saving boundary, the time value won't be an even number of days, it will be out by 1 hour (unless you cross two boundaries…)

PHP Timesheet calculate past 24hrs

I'm trying to calculate a timesheet i'm working on within a JS onChange event, the following works but it wont work past midnight, for example 23:00 - 01:00 returns 22 instead of 2 or rather 2.00 as I'd like it to report to 2 decimal places.
$startm = date_create({mS}); //create a php datetime object
$finishm = date_create({mF});
$t_diff = date_diff($startm, $finishm); //calculate the difference
{mT} = $t_diff->h + round($t_diff->i/60,2) + {mOt} + {mOt2} /24; //add everything up
The form has the following fields
Start Tme = mS - 24hr time
Finish Time = mF - 24hr time
Overtime = mOt - int
Overtime 2 = mOt2 - int
Total = mT - int

You can just add a check if $startm is past noon and $finishm is NOT past noon, $total -= 12. This of course won't work for shifts that last more than 24 hours, but that doesn't seem to be an acceptance criteria for your code.

Convert any String time to seconds

I'm trying to convert 15:00 (15minutes) to seconds though I get 54,000 when I use this below.
I'm trying to convert 15minutes to seconds.
S = '15:00';
D = "1/1/1 "
s = ( new Date(D+S) - new Date(D) )/1000
alert(s);
Though when I do the math, it's 60 x 15 = 900. How do I get 900, since the time is a random string.

Well if your format will always be "mm:ss" you could dome string parsing and do the math manually, of course this would need to be adjusted depending on the input format.
S = '15:25';
var times = S.split(":");
var minutes = times[0];
var seconds = times[1];
seconds = parseInt(seconds, 10) + (parseInt(minutes, 10) * 60);
alert(seconds);​
Note in the example I explicitly added 25 seconds just as demonstration.
http://jsfiddle.net/Jg4gB/

The time string '15:00' in JavaScript refers to the time of day 1500hr, or 3:00 p.m. American-style. That's 15 hours after midnight. That explains why you got 54,000 seconds.
If you wanted to express 15 minutes using your method of manipulating date strings, try '00:15:00'.