我正在跟踪一个教程,它运行正常,可以通过按Enter提交。不知何故,如果我添加一个提交按钮,它将通过仅添加一项并替换输入的最后一项来打破它。如何使用“提交”按钮和Enter键使它起作用?

这是一个工作示例:

https://codepen.io/sergestra/pen/WNeVEVE

(我已将“提交”按钮置于html注释中,请取消注释以查看我的问题。)



const form = document.querySelector('form');
const ul = document.querySelector('ul');
const button = document.querySelector('button');
const input = document.getElementById('item');
let itemsArray = localStorage.getItem('items') ? JSON.parse(localStorage.getItem('items')) : [];

localStorage.setItem('items', JSON.stringify(itemsArray));
const data = JSON.parse(localStorage.getItem('items'));

const liMaker = (text) => {
  const li = document.createElement('li');
  li.textContent = text;
  ul.appendChild(li);
}

form.addEventListener('submit', function (e) {
  e.preventDefault();

  itemsArray.push(input.value);
  localStorage.setItem('items', JSON.stringify(itemsArray));
  liMaker(input.value);
  input.value = "";
});

data.forEach(item => {
  liMaker(item);
});

button.addEventListener('click', function () {
  localStorage.clear();
  while (ul.firstChild) {
    ul.removeChild(ul.firstChild);
  }
  itemsArray = [];
});

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

<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">

  <title>New Tab App</title>

  <link rel="stylesheet" href="css/primitive.css">
</head>

<body>

  <div class="small-container">
    <h1>New Tab App</h1>

    <form>
      <input id="item" type="text" placeholder="New">
      <button>save note</button>
    </form>

    <h2>Items</h2>
    <ul></ul>

    <button>Clear All</button>
  </div>

  <script src="js/scripts.js"></script>
</body>

</html>

最佳答案

问题的原因:

这是因为在您的JavaScript中,您插入的button(以及“清除按钮”)上都有一个事件监听器。当您单击插入的button时,以下部分将导致删除:

  button.addEventListener('click', function () {
  localStorage.clear();
  while (ul.firstChild) {
    ul.removeChild(ul.firstChild);
  }
  itemsArray = [];
});


解决方法:

您可以给“清除按钮”指定一个ID,并在JavaScript中引用此ID,以将click-function(从上面)粘贴到:

以下对我有用的作品:

HTML:

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

<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">

  <title>New Tab App</title>

  <link rel="stylesheet" href="css/primitive.css">
</head>

<body>

  <div class="small-container">
    <h1>New Tab App</h1>

    <form>
      <input id="item" type="text" placeholder="New">
       <button>save note</button>
    </form>

    <h2>Items</h2>
    <ul></ul>

    <button id="buttonClear">Clear All</button>
  </div>

  <script src="js/scripts.js"></script>
</body>

</html>


JavaScript:

const form = document.querySelector('form');
const ul = document.querySelector('ul');
const button = document.querySelector('button');
const input = document.getElementById('item');
let itemsArray = localStorage.getItem('items') ? JSON.parse(localStorage.getItem('items')) : [];

localStorage.setItem('items', JSON.stringify(itemsArray));
const data = JSON.parse(localStorage.getItem('items'));

const liMaker = (text) => {
  const li = document.createElement('li');
  li.textContent = text;
  ul.appendChild(li);
}

form.addEventListener('submit', function (e) {
  e.preventDefault();

  itemsArray.push(input.value);
  localStorage.setItem('items', JSON.stringify(itemsArray));
  liMaker(input.value);
  input.value = "";
});

data.forEach(item => {
  liMaker(item);
});

clearbutton = document.getElementById("buttonClear");
clearbutton.addEventListener('click', function () {
   localStorage.clear();
   while (ul.firstChild) {
    ul.removeChild(ul.firstChild);
  }
  itemsArray = [];
});

10-07 19:21
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