我目前正在学习 JavaScript 数组，并尝试编写一个允许用户输入值的小程序。从那里，一旦他们单击“检查”按钮，JavaScript 就会循环遍历数组并检查是否在其中找到该值。 如果是，则打印一条成功消息，如果未找到该值，程序会提示用户重试。
我的问题是我无法循环遍历数组来查找值。以下是我的所有代码，非常感谢您的帮助！
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Check the value in the array </title>
</head>
<body>
<h1>Check to see if your value is found in an array</h1>
<label for="num">Enter value:</label>
<input type="text" id="num" name="num">
<br><br>
<button id="sub" onclick="printValue()">Check</button>
<br><br>
<div id="display"></div>
<script>
const numbers = [58, 4, 17, 32, 24, 53, 44, 99, 70, 56, 72,
43, 36, 51, 37, 46, 35, 25, 29, 64, 76, 21,
82, 94, 47, 12, 19, 31, 69, 81, 20, 91, 50,
3, 34, 79, 2, 27, 68, 52, 23, 22, 84, 18, 16,
33, 13, 39, 77, 8];
let value = document.getElementById("num");
let output = document.getElementById("display");
function printValue() {
for (let i = 0; i < numbers.length; i++) {
if (value == i) {
output.innerHTML = value.value;
output.innerHTML = "Value was found in the array!"
}
}
output.innerHTML = "Value is not found in array, please try again";
}
value.addEventListener("keyup", function(event){
if (event.keyCode === 13) {
event.preventDefault();
document.getElementById("sub").click();
}
})
</script>
</body>
</html>
您的代码中存在一些问题：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Check the value in the array </title>
</head>
<body>
<h1>Check to see if your value is found in an array</h1>
<label for="num">Enter value:</label>
<input type="text" id="num" name="num">
<br><br>
<button id="sub" onclick="printValue()">Check</button>
<br><br>
<div id="display"></div>
<script>
const numbers = [58, 4, 17, 32, 24, 53, 44, 99, 70, 56, 72,
43, 36, 51, 37, 46, 35, 25, 29, 64, 76, 21,
82, 94, 47, 12, 19, 31, 69, 81, 20, 91, 50,
3, 34, 79, 2, 27, 68, 52, 23, 22, 84, 18, 16,
33, 13, 39, 77, 8];
let inputEl = document.getElementById("num");
let output = document.getElementById("display");
function printValue() {
for (let i = 0; i < numbers.length; i++) {
if (inputEl.value == numbers[i]) {
output.innerHTML = inputEl.value;
output.innerHTML = "Value was found in the array!";
return;
}
}
output.innerHTML = "Value is not found in array, please try again";
}
inputEl.addEventListener("keyup", function(event){
if (event.keyCode === 13) {
event.preventDefault();
document.getElementById("sub").click();
}
})
</script>
</body>
</html>