Question

我创建了三个提示框来输入日期，月份和日期。我正在尝试显示出生年份，下一个转折年份并显示下一个生日的天数，小时数，分钟数和秒数。为此，我创建了日期对象。计算一切，但我没有得到答案。有人可以帮帮我吗？

代码：

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

    p{
        text-align: center;
        font-family: monospace;
        font-size: 20px;
    }
    </style>
    <title>lab14</title>


</head>
<body background= "lab14_images/birth.jpg">
    <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 startDate = 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 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 endDate = new Date(today.getFullYear() + 1, myMonth, myDay);
        // !!! WHERE is startDate defined???
        var s = (endDate.getTime() - startDate.getTime()) / 1000

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

    </script>
</body>
</html>

Answer 1

我修正了1错误：在实际使用

之前，已将值的分配移至endDate 。

请查看我的!!!评论。您正在使用既未定义也未初始化的变量。

使用代码段播放，并注意屏幕右下角的控制台错误。

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 birth = 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 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 endDate = new Date(today.getFullYear() + 1, myMonth, myDay); // !!! WHERE is startDate defined??? var secondsBetween = (endDate.getTime() - startDate.getTime()) / 1000 var seconds = Math.floor( (endDate/1000) % 60 ); var minutes = Math.floor( (endDate/1000/60) % 60 ); var hours = Math.floor( (endDate/(1000*60*60)) % 24 ); var days = Math.floor( endDate/(1000*60*60*24) ); var nextBirth = document.getElementById("nextBirth").innerHTML = "I am" + endDate + "Years old, and will turn"+ endDate + 1 +"in:"+ days +"days," + hours +"hours" + minutes +"minutes" + seconds +"seconds" ;

p{ text-align: center; font-family: monospace; font-size: 20px; }

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

Javascript：计算出生年份

1 个答案: