我想創建一個程式來確定給定年份是否是公歷中的閏年。在 HTML 檔案中，我創建了一個<input>帶有 id 的檔案，但我無法在 JS 中獲取該值。你能解釋一下是什么問題嗎？
let year = document.getElementById("year").value;
function checkLeapYear(year) {
if ((0 == year % 4) && (0 != year % 100) || (0 == year % 400)) {
console.log(year ' is a leap year');
} else {
console.log(year ' is not a leap year');
}
}
checkLeapYear(year);<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script src="script.js"></script>
</head>
<body>
Enter a year: <input type="text" id = "year">
<input type="button" id="button" onClick="checkLeapYear()" value="Check Leap Year">
</body>
</html>uj5u.com熱心網友回復：
原因是它let year = document.getElementById("year").value;在外面checkLeapYear()，當這條線執行時我們沒有為它輸入任何值
為了解決它，你需要把它放在year里面checkLeapYear()，這樣每次你都能得到最新的輸入值，也不需要，checkLeapYear(year);因為我們已經添加了onClick="checkLeapYear()"
function checkLeapYear() {
let year = document.getElementById("year").value;
if ((0 == year % 4) && (0 != year % 100) || (0 == year % 400)) {
console.log(year ' is a leap year');
} else {
console.log(year ' is not a leap year');
}
}<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script src="script.js"></script>
</head>
<body>
Enter a year: <input type="text" id = "year">
<input type="button" id="button" onClick="checkLeapYear()" value="Check Leap Year">
</body>
</html>轉載請註明出處，本文鏈接：https://www.uj5u.com/net/524319.html