Question

我正在开展一个小项目，我必须显示当前日期。我需要添加nth，st等等，具体取决于变量字符串的最后一个字母，但是当我在Web浏览器中检查HTML文件时，字符串不会显示。这是我的代码：

window.onload = function() {
   startDate();
}

function startDate() {
   var month = [
      "January",
      "February",
      "March",
      "April",
      "May",
      "June",
      "July",
      "August",
      "September",
      "October",
      "November",
      "December"
   ];

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

   var date = today.getDate();

   date = checkDate(date);

   document.getElementById("date").innerHTML = weekDay[today.getDay()] + " the " + date + " of " + month[today.getMonth()];
}

function checkDate(i) {
   if (i.slice(-1) == 1 && i !== 11) {
      i = i + "st";
   } else if (i.slice(-1) == 2 && i !== 12) {
      i = i + "nd";
   } else if (i.slice(-1) == 3 && i !== 13) {
      i = i + "rd";
   } else {
      i = i + "th";
   }

   return i;
}

这是我的HTML：

<!DOCTYPE html>
<html>
<head>
   <meta charset="utf-8">
   <link rel="stylesheet" href="style.css" />
</head>
<body>
   <div id="container">
      <div id="date"></div>
   </div>
   <script src="script.js"></script>
</body>
</html>

Answer 1

您的代码存在一些问题。首先，你如何定义'今天'？其次，切片功能未在Number对象上定义。通过这两个编辑您的工作代码：

window.onload = function() {
   startDate();
};
function startDate() {
   var month = [
      "January",
      "February",
      "March",
      "April",
      "May",
      "June",
      "July",
      "August",
      "September",
      "October",
      "November",
      "December"
   ];

   var weekDay = [
      "Sunday",
      "Monday",
      "Tuesday",
      "Wednesday",
      "Thursday",
      "Friday",
      "Saturday"
   ];
  var today = new Date();

   var date = today.getDate();

   date = checkDate(String(date));

   document.getElementById("date").innerHTML = weekDay[today.getDay()] + " the " + date + " of " + month[today.getMonth()];
}

function checkDate(i) {
   if (i.slice(-1) == 1 && i !== 11) {
      i = i + "st";
   } else if (i.slice(-1) == 2 && i !== 12) {
      i = i + "nd";
   } else if (i.slice(-1) == 3 && i !== 13) {
      i = i + "rd";
   } else {
      i = i + "th";
   }

   return i;
}

Answer 2

您需要在使用之前定义today，如下所示：

var today = new Date();
var date = today.getDate();

函数checkDate接收数字参数，但后来使用slice将其视为字符串：这会产生错误。您应该将其视为一个数字，例如i % 10：

function checkDate(i) {
   return (i % 10 == 1 && i !== 11) ? i + "st"
        : (i % 10 == 2 && i !== 12) ? i + "nd"
        : (i % 10 == 3 && i !== 13) ? i + "rd"
        : i + "th";
}

如果相同的变量等于字符串，则更改变量的值

2 个答案: