我正在尝试创建一个分页buti am reciving此错误
scripts.js：30 Uncaught TypeError：无法读取undefinedhideItems @ scripts.js的属性'style'：30（匿名函数）@ scripts.js：43 +
我不知道函数hideItems和showItems个别工作的问题是什么，但是给出错误，但是当我调用changePage时，只有在给定错误的情况下才能使用hideItems函数。
// Global Variables
var itemsPerPage = 10;
var list = document.getElementsByClassName('student-list');
var items = document.getElementsByClassName('student-item');
var actualPage = 1;
var buttons = document.getElementsByClassName("student-item");
var index;
// Count the numbrer of items in the list
var getNumberOfItems = function () {
var numbrerOfItems = items.length;
return (numbrerOfItems);
}
// Generating rhe number of pages
var getNumberOfPages = function () {
var numberOfPages = parseInt(getNumberOfItems() / itemsPerPage);
if ( getNumberOfItems() % itemsPerPage > 0 ){
numberOfPages += 1;
}
return numberOfPages;
}
var hideItems = function () {
for (var i = 0; i <= getNumberOfItems(); i++) {
items[i].style.display = "none";
console.log(i);
};
}
function showItemsByPage (page) {
for (var i = 0; i <= itemsPerPage - 1; i++) {
index = page * itemsPerPage - itemsPerPage + i;
items[index].style.display = "block";
console.log(index);
};
}
function changePage (number) {
document.addEventListener( "DOMContentLoaded", hideItems());
document.addEventListener( "DOMContentLoaded", showItemsByPage(number));
}
changePage(1);body{
background-color: #e1f1f6;
font-family: Helvetica, sans-serif;
color: #222;
}
.page{
margin: 50px auto;
width: 70%;
background-color: #fff;
border-radius: 5px;
padding: 50px;
}
.page-header{
margin-bottom: 20px;
}
.page-header h2{
float: left;
font-size: 22px;
text-transform: uppercase;
font-weight: bold;
color: #555;
}
.page-header .student-search{
float: right;
}
.page-header .student-search input{
border-radius: 5px;
border: 1px solid #eaeaea;
padding: 8px 15px;
font-size: 14px;
}
.page-header .student-search button{
border-radius: 5px;
border: 1px solid #eaeaea;
padding: 8px 15px;
font-size: 14px;
background-color: #4ba6c3;
color: #fff
}
.student-list{}
.student-item{
margin: 0 0 20px 0;
padding: 0 0 20px 0;
border-bottom: 1px solid #eaeaea;
}
.student-details{
width: 50%;
float: left;
}
.student-details .avatar{
width: 40px;
height: auto;
border-radius: 20px;
float: left;
margin-right: 14px
}
.student-details h3{
margin: 4px 0 2px 0;
font-weight: bold;
color: #4ba6c3;
}
.student-details .email{
color: #888;
font-size: 14px;
}
.joined-details{
width: 50%;
float: left;
text-align: right;
}
.joined-details .date{
margin-top: 15px;
display: block;
font-size: 14px;
color: #999;
}
.student-item:last-child{
margin: 0;
padding: 0;
border-bottom: none;
}
.pagination{
margin: 40px 0 0 0;
text-align: center;
}
.pagination li{
display: inline;
}
.pagination li a{
border: 1px solid #eaeaea;
border-radius: 5px;
padding: 3px 8px;
text-decoration: none;
color: #4ba6c3;
}
.pagination li a.active,
.pagination li a:hover{
background-color: #4ba6c3;
color: #fff;
}
.hidenItems{
display: none;
}
.showItems{
display: block;
}<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8"/>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<title>Students</title>
<link rel="stylesheet" href="css/reset.css">
<link rel="stylesheet" href="css/design.css">
</head>
<body>
<div class="page">
<div class="page-header cf">
<h2>Students</h2>
</div>
<ul class="student-list">
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/67.jpg">
<h3>iboya vat</h3>
<span class="email">iboya.vat@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 07/15/15</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/75.jpg">
<h3>aapo niskanen</h3>
<span class="email">aapo.niskanen@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 06/15/12</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/34.jpg">
<h3>phillip cox</h3>
<span class="email">phillip.cox@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 09/11/14</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/38.jpg">
<h3>zilda moreira</h3>
<span class="email">zilda.moreira@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 07/15/15</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/23.jpg">
<h3>lilou le gall</h3>
<span class="email">lilou.le gall@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 06/16/13</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/94.jpg">
<h3>lucy hall</h3>
<span class="email">lucy.hall@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 09/11/16</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/24.jpg">
<h3>mark colin</h3>
<span class="email">mark.colin@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 01/14/14</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/14.jpg">
<h3>sara alves</h3>
<span class="email">sara.alves@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 07/19/16</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/49.jpg">
<h3>ramon macrae</h3>
<span class="email">ramon.macrae@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 05/13/12</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/15.jpg">
<h3>connor taylor</h3>
<span class="email">connor.taylor@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 05/18/14</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/11.jpg">
<h3>aymeric morel</h3>
<span class="email">aymeric.morel@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 06/13/13</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/49.jpg">
<h3>lorenz otto</h3>
<span class="email">lorenz.otto@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 05/11/14</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/29.jpg">
<h3>karl williamson</h3>
<span class="email">karl.williamson@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 01/12/14</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/34.jpg">
<h3>ouassim heering</h3>
<span class="email">ouassim.heering@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 01/18/12</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/91.jpg">
<h3>roberto molina</h3>
<span class="email">roberto.molina@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 06/13/15</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/28.jpg">
<h3>jordan hubert</h3>
<span class="email">jordan.hubert@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 06/13/15</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/29.jpg">
<h3>melvin baker</h3>
<span class="email">melvin.baker@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 09/18/14</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/26.jpg">
<h3>everett gordon</h3>
<span class="email">everett.gordon@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 06/17/15</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/82.jpg">
<h3>aiden ma</h3>
<span class="email">aiden.ma@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 07/18/12</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/62.jpg">
<h3>florent gerard</h3>
<span class="email">florent.gerard@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 02/12/13</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/96.jpg">
<h3>amber chen</h3>
<span class="email">amber.chen@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 07/12/12</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/9.jpg">
<h3>alexandra davies</h3>
<span class="email">alexandra.davies@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 05/11/13</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/57.jpg">
<h3>sergio cole</h3>
<span class="email">sergio.cole@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 02/17/15</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/98.jpg">
<h3>edgar dixon</h3>
<span class="email">edgar.dixon@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 06/17/11</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/94.jpg">
<h3>kirk myers</h3>
<span class="email">kirk.myers@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 09/17/15</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/28.jpg">
<h3>ani hesseling</h3>
<span class="email">ani.hesseling@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 08/14/16</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/24.jpg">
<h3>victoire bonnet</h3>
<span class="email">victoire.bonnet@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 05/13/16</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/44.jpg">
<h3>marcos morales</h3>
<span class="email">marcos.morales@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 01/12/12</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/75.jpg">
<h3>nils neumann</h3>
<span class="email">nils.neumann@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 03/11/12</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/86.jpg">
<h3>emily harrison</h3>
<span class="email">emily.harrison@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 07/18/15</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/41.jpg">
<h3>matthew fortin</h3>
<span class="email">matthew.fortin@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 03/18/15</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/32.jpg">
<h3>charlotte steward</h3>
<span class="email">charlotte.steward@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 02/18/11</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/3.jpg">
<h3>marceau rodriguez</h3>
<span class="email">marceau.rodriguez@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 07/13/14</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/91.jpg">
<h3>hudson anderson</h3>
<span class="email">hudson.anderson@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 09/12/15</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/33.jpg">
<h3>warren phillips</h3>
<span class="email">warren.phillips@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 01/11/12</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/41.jpg">
<h3>leo niva</h3>
<span class="email">leo.niva@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 09/14/15</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/3.jpg">
<h3>hani prevoo</h3>
<span class="email">hani.prevoo@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 01/11/15</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/79.jpg">
<h3>veronica rodriguez</h3>
<span class="email">veronica.rodriguez@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 07/17/12</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/41.jpg">
<h3>ginestal das neves</h3>
<span class="email">ginestal.das neves@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 06/19/12</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/63.jpg">
<h3>devon barnes</h3>
<span class="email">devon.barnes@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 09/19/14</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/55.jpg">
<h3>brennan pierce</h3>
<span class="email">brennan.pierce@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 05/15/14</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/35.jpg">
<h3>zachary singh</h3>
<span class="email">zachary.singh@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 05/19/11</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/35.jpg">
<h3>arlo harris</h3>
<span class="email">arlo.harris@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 07/12/15</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/women/60.jpg">
<h3>hannah ginnish</h3>
<span class="email">hannah.ginnish@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 05/17/14</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/95.jpg">
<h3>goos brunt</h3>
<span class="email">goos.brunt@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 09/15/12</span>
</div>
</li>
<li class="student-item cf">
<div class="student-details">
<img class="avatar" src="https://randomuser.me/api/portraits/thumb/men/91.jpg">
<h3>eduard riedel</h3>
<span class="email">eduard.riedel@example.com</span>
</div>
<div class="joined-details">
<span class="date">Joined 06/12/15</span>
</div>
</li>
</ul>
<div class="pagination">
<ul>
<li>
<a class="active" href="#" value="1" onclick = "changePage(1)">1</a>
</li>
<li>
<a href="#" onclick = "changePage(2)">2</a>
</li>
<li>
<a href="#" onclick = "changePage(3)">3</a>
</li>
<li>
<a href="#" onclick = "changePage(4)">4</a>
</li>
<li>
<a href="#" onclick = "changePage(5)">5</a>
</li>
</ul>
</div>
</div>
<script type="text/javascript" src= "js/scripts.js">
</script>
</body>
</html>
答案 0 :(得分：0)
似乎是典型的“Off by one”错误。
更改
for (var i = 0; i <= getNumberOfItems(); i++)
到
for (var i = 0; i < getNumberOfItems(); i++)