I need to get the percentage of the day that has elapsed in 24 hour time. 24:00 being 100%, 12:00 being 50%, and 00:00 being 0%. Here is what I have, however, the percentage is wrong:
function currentTime() {
let date = new Date();
let hh = date.getHours();
let mm = date.getMinutes();
let ss = date.getSeconds();
let ms = date.getMilliseconds();
let session = "AM";
if(hh === 0){
hh = 12;
}
if(hh > 12){
hh = hh - 12;
session = "PM";
}
hh = (hh < 10) ? "0" + hh : hh;
mm = (mm < 10) ? "0" + mm : mm;
ss = (ss < 10) ? "0" + ss : ss;
let time = hh + ":" + mm + " " + session;
document.getElementById("clock").innerText = time;
let t = setTimeout(function(){ currentTime() }, 1000);
percentage = (hh / 36 + mm / (60 * 24)) * 1000;
document.getElementById("percentage").innerText = percentage;
}
currentTime();
percentage();<div>
<span id="percentage" onload="percentage()"></span>% elapsed
</div>I would like to understand what I'm doing wrong and how this can be corrected. Thanks.
So, I'd reccomend forgoing the whole logic of hours and minutes and stuff.
You could simply say:
function getDatePercent() {
let dateInQuestion = new Date(Date.now())
//we are copying the value of the date object into a new object:
let startOfDay = new Date(dateInQuestion.valueOf())
//define the beginning of the day. Depending on time zone and browser, this may need tweaking:
startOfDay.setHours(0)
startOfDay.setMinutes(0)
startOfDay.setSeconds(0)
startOfDay.setMilliseconds(0)
let lengthOfDay = 1000 * 60 * 60 * 24 //ms in a day
//subtract to find time since beginning of the day, divide by
//number of ms in day, and then multiply by 100 to get percentage
return ( dateInQuestion.valueOf() - startOfDay.valueOf() ) / lengthOfDay * 100
}
console.log(getDatePercent())
This allows us to more directly measure how many ms have eslapsed since the start of the day compared to how many ms there are in the day.
Note: this snippet was running based on UTC time, not local time. That's why I didn't originally make it a snippet. Someone edited my answer.