CODEWITHSUNDEEP
javascriptdatetime
jiggy1965
jiggy1965

Reputation: 177

How to calculate milliseconds since beginning of the day?

I've specified a specific time on a certain day. Now I wish to calculate the milliseconds from the beginning of that specific day to the set time of that day? I was hoping to do that with below code, but instead it shows nothing? What am I doing wrong?

var now = new Date().getTime();
var oneday = 1000 * 60 * 60 * 24;
var countDownDate = new Date("January 10, 2018 00:01").getTime();
var countDownStart = new Date(countDownDate.getFullYear(), countDownDate.getMonth(), countDownDate.getDate(), 0, 0, 0, 0); 
var countDownTime = countDownDate.getTime() - countDownStart.getTime();

var div = document.getElementById('result'); 
div.innerText = countDownTime;

I specify the countDownDate. Then I mark the beginning of that countDownDate into the variable countDownStart. Next I calculate the time passed since 00:00 of January 10 to 00:01 of January 10 by subtracting countDownStart from countDownDate. But no result is shown...

Upvotes: 0

Views: 77

Answers (2)

Spencer Wieczorek
Spencer Wieczorek

Reputation: 21575

Your logic is fine here. The only issue is this line here:

var countDownDate = new Date("January 10, 2018 00:01").getTime();

Since you used .getTime() the variable countDownDate is no longer a date. As such in the following statementcountDownDate.getFullYear() and forward isn't going to work. Simply remove .getTime() and it will work as expected:

var now = new Date().getTime();
var oneday = 1000 * 60 * 60 * 24;
var countDownDate = new Date("January 10, 2018 00:01");
var countDownStart = new Date(countDownDate.getFullYear(), countDownDate.getMonth(), countDownDate.getDate(), 0, 0, 0, 0); 
var countDownTime = countDownDate.getTime() - countDownStart.getTime();

console.log(countDownTime)

Upvotes: 0

31piy
31piy

Reputation: 23859

Your code has only one issue, and that is that you've assigned the result of .getTime() to countDownDate, which will be a number.

That's why JavaScript cannot call getFullYear, or any other function on that number, because those will be invalid calls.

To correct that, just remove the .getTime(), and it will work fine.

var now = new Date().getTime();
var oneday = 1000 * 60 * 60 * 24;
var countDownDate = new Date("January 10, 2018 00:01");
var countDownStart = new Date(countDownDate.getFullYear(), countDownDate.getMonth(), countDownDate.getDate(), 0, 0, 0, 0);
var countDownTime = countDownDate.getTime() - countDownStart.getTime();

var div = document.getElementById('result');
div.innerText = countDownTime;
<div id="result">
  <div>

Upvotes: 2

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