网站中的搜索栏无法按预期工作

Question

我正在为 cs50 中的网络轨道制作一个快速网站，但我的搜索栏功能有问题。我试图做到这一点，当您单击搜索栏时，将出现一个项目列表（主页、第 2 页、第 3 页、第 4 页）。附加的 JS 函数也应该做到这一点，因此当您在选项列表中输入相应的字母时，具有匹配字母的选项将保留，而没有匹配字母的选项将消失。当我运行网站上的代码时，它根本不起作用。附上代码片段和图片。

总结：问题 1 - 为什么代码没有隐藏没有正确字母的结果？

问题 2 - 为什么当我没有被选中时代码没有隐藏所有列表选项？

function search()
{
    var input, filter, ul, li, a, i, txtValue;
    input = document.getElementById("pgsearchbar").value;
    filter = input.toUpperCase();
    ul = document.getElementById("searchitems");
    li = ul.getElementsByTagName("li");

    for (i = 0; i < li.length; i++)
    {
        finder = li[i].getElementsByTagName("a")[0];
        letter = finder.textContent || finder.innerText;
        if (letter.toUpperCase().indexOf(filter) > -1)
        {
            li[i].style.display = "";
        }
        else
        {
            li[i].style.display = "none";
        }
    }
}

.pageselector
{
    position:absolute;
    bottom:10%;
    left:45%;
}

.banner
{
    background-image:url("sky.jpg");
    padding:60px;
    color:lightblue;
}

.banntxt
{
    font-size:50px;
    text-shadow: -1px -1px 0 #000, 1px -1px 0 #000, -1px 1px 0 #000, 1px 1px 0 #000;
    font-family:"Faster One";
}

.navbar-brand
{
    font-family:"Faster One";
    font-size:25px;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<!DOCTYPE html>

<html lang="en">
    <head>
        <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css" integrity="sha384-JcKb8q3iqJ61gNV9KGb8thSsNjpSL0n8PARn9HuZOnIxN0hoP+VmmDGMN5t9UJ0Z" crossorigin="anonymous">
        <link href="styles.css" rel="stylesheet">
        <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Faster One">
        <title>My Webpage</title>
    </head>
    <body>
        <div>
            <div class="banner">
                <h1 class="banntxt">abcdefghijklmnop</h1>
            </div>
            <nav class="navbar navbar-light" style="background-color: #e3f2fd;">
                <span class="navbar-brand mb-0 h1">ABC</span>
                <h2 style="font-size:26px;">Contact us at: abcdefgh@gmail.com | ###-####-####</h2>
                <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
                    <span class="navbar-toggler-icon"></span>
                </button>
                <div class="collapse navbar-collapse" id="navbarNav">
                    <ul class="navbar-nav">
                        <li class="nav-item active">
                            <a class="nav-link" style="color:grey;">Home</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link" href="abme.html" style="color:black;">About me</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link" href="#" style="color:black;">Blah</a>
                        </li>
                        <li>
                            <form class="form-inline">
                                <input id="pgsearchbar" class="form-control mr-sm-2" type="search" onkeyup"search()" placeholder="Search" aria-label="Search">
                                <ul id="searchitems">
                                    <li>
                                        <a href="index.html">homepage</a>
                                    </li>
                                    <li>
                                        <a href="page2.html">page2</a>
                                    </li>
                                    <li>
                                        <a href="page3.html">page3</a>
                                    </li>
                                    <li>
                                        <a href="page3.html">page4</a>
                                    </li>
                                </ul>
                                <button class="btn btn-outline-info my-2 my-sm-0" type="submit">Search</button>
                            </form>
                        </li>
                    </ul>
                </div>
            </nav>

        </div>
        <div style="position:absolute; bottom:10%; left:48.04%;">
            <div class="btn-group" role="group" aria-label="Button group with nested dropdown">
                <div class="btn-group" role="group">
                    <button id="dropdownMenuButton" type="button" class="btn btn-secondary dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                        Page 1
                    </button>
                    <div class="dropdown-menu" aria-labelledby="btnGroupDrop1">
                        <a class="dropdown-item disabled">1</a>
                        <a class="dropdown-item" href="page2.html">2</a>
                        <a class="dropdown-item" href="page3.html">3</a>
                        <a class="dropdown-item" href="page4.html">4</a>

                    </div>
                </div>
                <button onclick="window.location.href='page2.html';" type="btn" class="btn btn-secondary">-></button>
            </div>
        </div>
        <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js"
        integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo"
        crossorigin="anonymous"></script>
        <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.6/umd/popper.min.js"
        integrity="sha384-wHAiFfRlMFy6i5SRaxvfOCifBUQy1xHdJ/yoi7FRNXMRBu5WHdZYu1hA6ZOblgut"
        crossorigin="anonymous"></script>
        <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/js/bootstrap.min.js"
        integrity="sha384-B0UglyR+jN6CkvvICOB2joaf5I4l3gm9GU6Hc1og6Ls7i6U/mkkaduKaBhlAXv9k"
        crossorigin="anonymous"></script>
        <script type="text/javascript" src="functions.js"></script>

    </body>
</html>

外观：

Answer 1

您在输入时缺少事件侦听器

document.getElementById('pgsearchbar').addEventListener('input', ()=>{
search()
})

Fiddle 示例：https://jsfiddle.net/bg8wyrhz/

Answer 2

您的 html 有误。从以下位置更改此行：

<input id="pgsearchbar" class="form-control mr-sm-2" type="search" onkeyup"search()" placeholder="Search" aria-label="Search">
                                                                        ^^^^

至：

<input id="pgsearchbar" class="form-control mr-sm-2" type="search" onkeyup="search()" placeholder="Search" aria-label="Search">
                                                                         ^^^^

function search() {
var input, filter, ul, li, a, i, txtValue;
input = document.getElementById("pgsearchbar").value;
filter = input.toUpperCase();
ul = document.getElementById("searchitems");
li = ul.getElementsByTagName("li");

for (i = 0; i < li.length; i++)
{
    finder = li[i].getElementsByTagName("a")[0];
    letter = finder.textContent || finder.innerText;
    if (letter.toUpperCase().indexOf(filter) > -1)
    {
        li[i].style.display = "";
    }
    else
    {
        li[i].style.display = "none";
    }
}
}

.pageselector
{
    position:absolute;
    bottom:10%;
    left:45%;
}

.banner
{
    background-image:url("sky.jpg");
    padding:60px;
    color:lightblue;
}

.banntxt
{
    font-size:50px;
    text-shadow: -1px -1px 0 #000, 1px -1px 0 #000, -1px 1px 0 #000, 1px 1px 0 #000;
    font-family:"Faster One";
}

.navbar-brand
{
    font-family:"Faster One";
    font-size:25px;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css">
  <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Faster One">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.6/umd/popper.min.js"></script>
  <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/js/bootstrap.min.js"></script>
  
  
  <div>
    <div class="banner">
        <h1 class="banntxt">abcdefghijklmnop</h1>
    </div>
    <nav class="navbar navbar-light" style="background-color: #e3f2fd;">
        <span class="navbar-brand mb-0 h1">ABC</span>
        <h2 style="font-size:26px;">Contact us at: abcdefgh@gmail.com | ###-####-####</h2>
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
        </button>
        <div class="collapse navbar-collapse" id="navbarNav">
            <ul class="navbar-nav">
                <li class="nav-item active">
                    <a class="nav-link" style="color:grey;">Home</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="abme.html" style="color:black;">About me</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="#" style="color:black;">Blah</a>
                </li>
                <li>
                    <form class="form-inline">
                        <input id="pgsearchbar" class="form-control mr-sm-2" type="search" onkeyup="search()" placeholder="Search" aria-label="Search">
                        <ul id="searchitems">
                            <li>
                                <a href="index.html">homepage</a>
                            </li>
                            <li>
                                <a href="page2.html">page2</a>
                            </li>
                            <li>
                                <a href="page3.html">page3</a>
                            </li>
                            <li>
                                <a href="page3.html">page4</a>
                            </li>
                        </ul>
                        <button class="btn btn-outline-info my-2 my-sm-0" type="submit">Search</button>
                    </form>
                </li>
            </ul>
        </div>
    </nav>

</div>
<div style="position:absolute; bottom:10%; left:48.04%;">
    <div class="btn-group" role="group" aria-label="Button group with nested dropdown">
        <div class="btn-group" role="group">
            <button id="dropdownMenuButton" type="button" class="btn btn-secondary dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                Page 1
            </button>
            <div class="dropdown-menu" aria-labelledby="btnGroupDrop1">
                <a class="dropdown-item disabled">1</a>
                <a class="dropdown-item" href="page2.html">2</a>
                <a class="dropdown-item" href="page3.html">3</a>
                <a class="dropdown-item" href="page4.html">4</a>

            </div>
        </div>
        <button onclick="window.location.href='page2.html';" type="btn" class="btn btn-secondary">-></button>
    </div>
</div>

网站中的搜索栏无法按预期工作

Search bar in website doesnt work as intended

html

javascript

css

cs50