版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/u011240016/article/details/84185265
界面：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" integrity="sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M" crossorigin="anonymous">
<title>Item Lister</title>
</head>
<body>
<header id="main-header" class="bg-success text-white p-4 mb-3">
<div class="container">
<div class="row">
<div class="col-md-6">
<h1 id="header-title">Item Lister</h1>
</div>
<div class="col-md-6 align-self-center">
<input type="text" class="form-control" id="filter" placeholder="Search Items...">
</div>
</div>
</div>
</header>
<div class="container">
<div id="main" class="card card-body">
<h2 class="title">Add Items</h2>
<form id="addForm" class="form-inline mb-3">
<input id="item" type="text" class="form-control mr-2">
<!-- <select class="form-control mr-2">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select> -->
<input type="submit" class="btn btn-dark" value="Submit">
</form>
<h2 class="title">Items</h2>
<ul id="items" class="list-group">
<li class="list-group-item">Item 1
<button class="btn btn-danger btn-sm float-right delete">X</button>
</li>
<li class="list-group-item">Item 2
<button class="btn btn-danger btn-sm float-right delete">X</button>
</li>
<li class="list-group-item">Item 3
<button class="btn btn-danger btn-sm float-right delete">X</button>
</li>
<li class="list-group-item">Item 4
<button class="btn btn-danger btn-sm float-right delete">X</button>
</li>
<!-- <li>Item 5</li> -->
</ul>
<div id="output"></div>
<br/>
<button id="button" class="btn btn-dark btn-block">Click Here</button>
<div style="width: 400px; height: 200px; background: #f4f4f4" id="box">
<h3>Hello</h3>
</div>
</div>
</div>
<!-- <script src="dom.js"></script> -->
<script src="main.js"></script>
</body>
</html>
逻辑：
// main.js
var form = document.getElementById('addForm')
var itemList = document.getElementById('items')
var filter = document.getElementById('filter')
form.addEventListener('submit', addItem)
itemList.addEventListener('click', removeItem)
filter.addEventListener('keyup', filterItems)
// add item
function addItem(e) {
e.preventDefault()
var newItem = document.getElementById('item').value
var li = document.createElement('li')
li.className = 'list-group-item'
// console.log(li)
// add text node with the input data
li.appendChild(document.createTextNode(newItem))
// Create del button
var deleteBtn = document.createElement('button')
// add classes to delete button
deleteBtn.className = 'btn btn-danger btn-sm float-right delete'
// append text node
deleteBtn.appendChild(document.createTextNode('X'))
li.appendChild(deleteBtn)
itemList.appendChild(li)
}
function removeItem(e) {
// console.log(1)
if (e.target.classList.contains('delete')) {
if(confirm('Are you sure?')) {
var li = e.target.parentElement;
itemList.removeChild(li)
}
}
}
// Filter items
function filterItems(e) {
// convert to lowercase
var text = e.target.value.toLowerCase();
var items = itemList.getElementsByTagName('li');
// console.log(itemList)
Array.from(items).forEach(function(item){
var itemName = item.firstChild.textContent;
// console.log(itemName);
if(itemName.toLowerCase().indexOf(text) != -1) {
item.style.display = 'block';
} else {
item.style.display = 'none';
}
});
}
效果就是能对搜索框进行过滤，可以添加列表，可以删除已经存在的条目，是非常常见的用法，代码片段可以参考复用。
END.