Question

我知道有很多主题，但没有人回答我的问题。我必须在窗口中打印按字典顺序排列的最小和最大的属性。但我得到了错误Cannot set property of innerHTML of null at solve。这是我的HTML：

<!DOCTYPE html>
<html lang="en">

<head>
     <title>Loops Homework</title>
     <meta charset="UTF-8">

</head>

<body>
    <span>Problem 1</span>
    <button onclick="solve()">Print</button>
    <div id="answer1">Answer will appear here</div>
    <script src="LexicographicallyProp.js" type="text/javascript"></script>
</body>

</html>

关注javascript文件：

function solve() {
let smallest = 'zzz',
    largest = '',
    prop,
    div1 = document.getElementById('#answer1');

for (prop in document) {
    if (prop < smallest) {
        smallest = prop;
    }

    if (prop > largest) {
        largest = prop;
    }
}
div1.innerHTML = 'Smallest property in DOCUMENT: ' + smallest + ' ; Largest prop in DOCUMENT: ' + largest;

}

Answer 1

应该是：

div1 = document.getElementById('answer1');

'#answer1'是HTML元素ID的jQuery表示法。

Answer 2

请更改以下行：

div1 = document.getElementById('#answer1');

使用：

div1 = document.getElementById('answer1');

无法设置属性innerHTML为null（javascript）

2 个答案: