Question

我正在尝试显示下一个生日的天，小时，分钟和秒。生日是通过提示值计算的。我计算了秒，分，小时和天。但是我得到了错误的价值，例如＆＃34; 0＆＃34 ;.我的代码有什么问题？

代码：

<!DOCTYPE html>
<html>
<head>
    <style>

    p{
        text-align: center;
        font-family: monospace;
        font-size: 20px;
    }
    </style>
    <title>trail</title>

</head>
<body>
    <h1 style="text-align: center; font-family: monospace;"> My age </h1>
    <p id="dateField"> </p>
    <p id="birthField"> </p>
    <p id="nextBirth"> </p>

    <script>    

        var monthNames = ["January", "February", "March", "April", "May", "June",
          "July", "August", "September", "October", "November", "December"
        ];

        var days = ["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"];

        var today = new Date(); 

        var myMonth = prompt("What month were you born in?");
        var myDay = prompt("What day were you born on?");
        var myYear = prompt("What year were you born in?");

        var birthday = new Date(myYear, myMonth, myDay);  

        var dateLoc = document.getElementById("dateField").innerHTML = "Today is " + today;

        var birthField = document.getElementById("birthField")
        .innerHTML = "I was born on " + monthNames[myMonth - 1] + ' ' + myDay + ',' + myYear + '.' 
        + '(' + myMonth + '/' + myDay + '/' + myYear + ')';

        var years = today.getFullYear() - birthday.getFullYear();  

        var seconds = Math.floor( (years/1000) % 60 );
        var minutes = Math.floor( (years/1000/60) % 60 );
        var hours = Math.floor( (years/(1000*60*60)) % 24 );
        var days = Math.floor( years/(1000*60*60*24) );

        var nextBirth = document.getElementById("nextBirth").innerHTML = "I am " + years + "  Years old, and will turn " + (years + 1 ) + " in:" + "<br>" + days + " days," + hours + "hours," + minutes + "minutes," + seconds + "seconds";
    </script>
</body>
</html>

Answer 1

（不考虑闰年/秒等）

使用new Date()过去的月份从1月开始为0。你可以使用：

var myMonth = prompt("What month were you born in?") - 1;

现在您的变量birthday将存储正确的月份。

对于birthField，您可以将monthNames[my Month - 1]更改为monthNames[my Month]

对于years，您只是减去当年的出生年份。如果今年的生日没有发生，years将会关闭。我们稍后会解决这个问题。

我们需要找出用户下一个生日的正确日期。这是今年或明年。将今年生日的日期存储在变量中可能很方便：

var thisYearsBirthday = new Date(today.getFullYear(), myMonth, myDay);

我们可以存储用户即将到来的生日年份的变量，假设它是明年：

var nextBirthdayYear = today.getFullYear() + 1;

然后，我们可以检查将来是否thisYearsBirthday，如果是，那么今年将nextBirthdayYear更改为。我们还应该更改years以反映用户今年的生日还没有发生。

if ( today < thisYearsBirthday ) {
  nextBirthdayYear = today.getFullYear();
  years = years - 1;
}

现在我们可以存储用户下一个正确的生日：

var nextBirthday = new Date( nextBirthdayYear, myMonth, myDay );

我们可以存储在用户下一个生日之前剩余的毫秒数：

var milliseconds = nextBirthday - today;

您的变量seconds，minutes，hours和days不是基于年的公式，而是基于毫秒。我们应该将milliseconds变量放在那里：

var seconds = Math.floor( (milliseconds/1000) % 60 );
var minutes = Math.floor( (milliseconds/1000/60) % 60 );
var hours = Math.floor( (milliseconds/(1000*60*60)) % 24 );
var days = Math.floor( milliseconds/(1000*60*60*24) );

这将导致显示下一个生日的正确天数，小时数，分钟数和秒数。

Answer 2

嗨，你错过了计算下一个生日，它应该低于代码

var today = new Date();

var myMonth = prompt("What month were you born in?");
var myDay = prompt("What day were you born on?");
var myYear = prompt("What year were you born in?");

var birthday = new Date(myYear, myMonth, myDay);
console.log(birthday);

var dateLoc = document.getElementById("dateField").innerHTML = "Today is " + today;

var birthField = document.getElementById("birthField")
    .innerHTML = "I was born on " + monthNames[myMonth - 1] + ' ' + myDay + ',' + myYear + '.'
    + '(' + myMonth + '/' + myDay + '/' + myYear + ')';

var milliseconds,seconds,minutes,hours,days;

var years = today.getFullYear() - birthday.getFullYear();

//Here is my code 
 myMonth--;// Because of Month index is 0-11
var nextBirthday = (new Date(today.getFullYear(), myMonth, myDay))<today?(new Date(today.getFullYear()+1, myMonth, myDay)):(new Date(today.getFullYear(), myMonth, myDay)) //checking is passed or not
var diff = nextBirthday-today;

milliseconds=diff%1000;
diff=(diff-(milliseconds))/1000;
console.log(diff);
seconds=diff%60
console.log(diff);
diff=(diff-seconds)/60;
console.log(diff);
minutes=diff%60
diff=(diff-minutes)/60;
console.log(diff);
hours=diff%24
days=(diff-hours)/24;
console.log(diff);

var nextBirth = document.getElementById("nextBirth").innerHTML = "I am " + years + "  Years old, and will turn " + (years + 1 ) + " in:" + "<br>" + days + " days," + hours + "hours," + minutes + "minutes," + seconds + "seconds";

您可以在

下找到工作代码

popFirst()

Answer 3

所以你要在下一个生日那天得到几天，几小时，几分钟和几秒钟。问题是你的等式基于太少的信息。这是问题所在。

var years = today.getFullYear() - birthday.getFullYear();
//with example values: 30 = 2017 - 1987

//Here you try to get values from 30
var seconds = Math.floor( (years/1000) % 60 );
var minutes = Math.floor( (years/1000/60) % 60 );
var hours = Math.floor( (years/(1000*60*60) ) % 24 );
var days = Math.floor( years/(1000*60*60*24) );

麻烦的是Date.prototype.getFullYear（）只返回年份，所以从另一个中减去一个'fullYear'只会给你年龄，但不会返回任何其他信息。要获得您想要的结果，您需要找到一些方法来传递更多信息。我的建议是添加如下内容。

var years = today.getFullYear() - birthday.getFullYear();

//Edit: it's been pointed out that not everyone's next birthday is next year. This solution still works, but we need to add conditional logic to this next statement.
if ( today.getMonth() > birthday.getMonth() || (today.getMonth() === birthday.getMonth() && today.getDay() >= birthday.getDay() )) {
   var nextYear = today.getFullYear()+1;
}

var nextBirthday = birthday;
nextBirthday.setFullYear(nextYear);

//This converts nextBithday into milliseconds since 1970. Use Date.getTime() to do the same to today and subtract.
var timeToNextBday = nextBirthday - today.getTime();

//From here use math to get the precise days and time until your next birthday

JavaScript：显示下一个生日的天，小时，分钟和秒

3 个答案: