javascript - 如何获得两个日期和时间之间的差异并显示时间正在流逝

Question

我有两个变量，第一个变量是从日期时间选择器获取日期和时间值，第二个变量是选择当前日期和时间的值。现在我想要它们之间的区别，并以文本形式显示，例如计时器耗尽。

<input type="date" id="dates">
    <input type="time"  id="times">

var time=new Date().toLocaleTimeString('en-GB');
        var res = time.slice(0,-3);
        var today = new Date();
        var dd = String(today.getDate()).padStart(2, '0');
        var mm = String(today.getMonth() + 1).padStart(2, '0');
        var yyyy = today.getFullYear();
        today = yyyy + '-' + mm + '-' + dd;
        var current=today+" "+res; // Here i am getting the value of current date and time

 var datetime=dates.value+" " +times.value; // This value is from date time picker 

 var t=datetime-current;
        alert(t); //here the output is always NaN

我想要两个日期时间之间的差异，并显示文本，如计时器正在运行

Answer 1

根据假定值更正了您的代码。

var dates = {
        value: '2019-09-06'
    };
    var times = {
        value: '10:55:00'
    };

    var time=new Date().toLocaleTimeString('en-GB');
    var res = time.slice(0,-3);
    var today = new Date();
    var dd = String(today.getDate()).padStart(2, '0');
    var mm = String(today.getMonth() + 1).padStart(2, '0');
    var yyyy = today.getFullYear();
    today = yyyy + '-' + mm + '-' + dd;
    var current=today+" "+res; // Here i am getting the value of current date and time

    var datetime=dates.value+" " +times.value; // This value is from date time picker

    var t= ( new Date( datetime ) ).getTime() - ( new Date( current ) ).getTime();
    alert(t);