假设你有两个Date对象，你可以减去它们，以毫秒为单位得到差值:

var difference = date2 - date1;

从那里，您可以使用简单的算术来推导其他值。

这段代码将返回两个日期的差值(以天为单位):

const previous_date = new Date("2019-12-23");
const current_date = new Date();

const current_year = current_date.getFullYear();
const previous_date_year = 
previous_date.getFullYear();

const difference_in_years = current_year - 
previous_date_year;

let months = current_date.getMonth();
months = months + 1; // for making the indexing 
// of months from 1

for(let i = 0; i < difference_in_years; i++){
months = months + 12;
}

let days = current_date.getDate();

days = days + (months * 30.417);

console.log(`The days between ${current_date} and 
${previous_date} are : ${days} (approximately)`);

基于javascript运行时原型实现，您可以使用简单的算术减去日期如下所示

var sep = new Date(2020, 07, 31, 23, 59, 59);
var today = new Date();
var diffD = Math.floor((sep - today) / (1000 * 60 * 60 * 24));
console.log('Day Diff: '+diffD);

差值返回以毫秒为单位的答案，然后你必须通过除法转换它:

按1000换算成秒 通过1000×60转换为分钟 通过1000×60×60转换为小时 通过1000×60×60×24转换为日

function daysInMonth (month, year) { return new Date(year, month, 0).getDate(); } function getduration(){ let A= document.getElementById("date1_id").value let B= document.getElementById("date2_id").value let C=Number(A.substring(3,5)) let D=Number(B.substring(3,5)) let dif=D-C let arr=[]; let sum=0; for (let i=0;i<dif+1;i++){ sum+=Number(daysInMonth(i+C,2019)) } let sum_alter=0; for (let i=0;i<dif;i++){ sum_alter+=Number(daysInMonth(i+C,2019)) } let no_of_month=(Number(B.substring(3,5)) - Number(A.substring(3,5))) let days=[]; if ((Number(B.substring(3,5)) - Number(A.substring(3,5)))>0||Number(B.substring(0,2)) - Number(A.substring(0,2))<0){ days=Number(B.substring(0,2)) - Number(A.substring(0,2)) + sum_alter } if ((Number(B.substring(3,5)) == Number(A.substring(3,5)))){ console.log(Number(B.substring(0,2)) - Number(A.substring(0,2)) + sum_alter) } time_1=[]; time_2=[]; let hour=[]; time_1=document.getElementById("time1_id").value time_2=document.getElementById("time2_id").value if (time_1.substring(0,2)=="12"){ time_1="00:00:00 PM" } if (time_1.substring(9,11)==time_2.substring(9,11)){ hour=Math.abs(Number(time_2.substring(0,2)) - Number(time_1.substring(0,2))) } if (time_1.substring(9,11)!=time_2.substring(9,11)){ hour=Math.abs(Number(time_2.substring(0,2)) - Number(time_1.substring(0,2)))+12 } let min=Math.abs(Number(time_1.substring(3,5))-Number(time_2.substring(3,5))) document.getElementById("duration_id").value=days +" days "+ hour+" hour " + min+" min " } <input type="text" id="date1_id" placeholder="28/05/2019"> <input type="text" id="date2_id" placeholder="29/06/2019"> <br><br> <input type="text" id="time1_id" placeholder="08:01:00 AM"> <input type="text" id="time2_id" placeholder="00:00:00 PM"> <br><br> <button class="text" onClick="getduration()">Submit </button> <br><br> <input type="text" id="duration_id" placeholder="days hour min">

我想这个就可以了。

let today = new Date();
let form_date=new Date('2019-10-23')
let difference=form_date>today ? form_date-today : today-form_date
let diff_days=Math.floor(difference/(1000*3600*24))

var d1=new Date(2011,0,1); // jan,1 2011
var d2=new Date(); // now

var diff=d2-d1,sign=diff<0?-1:1,milliseconds,seconds,minutes,hours,days;
diff/=sign; // or diff=Math.abs(diff);
diff=(diff-(milliseconds=diff%1000))/1000;
diff=(diff-(seconds=diff%60))/60;
diff=(diff-(minutes=diff%60))/60;
days=(diff-(hours=diff%24))/24;

console.info(sign===1?"Elapsed: ":"Remains: ",
             days+" days, ",
             hours+" hours, ",
             minutes+" minutes, ",
             seconds+" seconds, ",
             milliseconds+" milliseconds.");