javascript案例集 javascript小案例
转载
循环精灵图和显示隐藏文本框内容
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
}
.box {
width: 250px;
margin: 100px auto;
}
.box li {
float: left;
width: 24px;
height: 24px;
background-color: pink;
margin: 15px;
list-style: none;
background: url(img/sprite.png) no-repeat;
}
</style>
</head>
<body>
<div class="box">
<ul>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
</ul>
</div>
<script>
//1.获取元素 所有的li
var lis = document.querySelectorAll('li');
for (var i = 0; i < lis.length; i++) {
var wz = i * 44;
lis[i].style.backgroundPosition = '0 -' + wz + 'px';
}
</script>
</body>
</html>
显示隐藏文本框内容
<!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">
<title>Document</title>
<style>
input {
color: #999;
}
</style>
</head>
<body>
<input type="text" value="内容">
<script>
// 1.获取元素
var text = document.querySelector('input');
// 2.注册事件 获得焦点事件 onfocus
text.onfocus = function() {
// console.log('得到了焦点');
if (this.value === '内容') {
this.value = '';
}
// 获得焦点需要把文本框里面的文字颜色变黑
this.style.color = '#333';
}
// 3. 注册事件 失去焦点事件 onblur
text.onblur = function() {
// console.log('失去了焦点');
if (this.value === '') {
this.value = '内容';
}
// 失去焦点需要把文本框里面的文字颜色变浅色
this.style.color = '#999';
}
</script>
</body>
</html>
密码框格式提示错误信息
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
div {
width: 600px;
margin: 100px auto;
}
.message {
display: inline-block;
font-size: 12px;
color: #999;
background: url(img/mess.png) no-repeat left center;
padding-left: 20px;
}
.wrong {
color: red;
background: url(img/wrong.png) no-repeat left center;
}
.right {
color: green;
background: url(img/right.png) no-repeat left center;
}
</style>
</head>
<body>
<div class="reg">
<input type="password" class="ipt">
<p class="message">请输入6~16位密码</p>
</div>
<script>
//1.获取元素
var ipt = document.querySelector('.ipt');
var message = document.querySelector('.message');
//2.注册事件 失去焦点
ipt.onblur = function() {
//根据表单里面值的长度ipt.value.length
if (this.value.length < 6 || this.value.length > 16) {
message.className = 'message wrong';
message.innerHTML = '您输入的不对,要求6~16位';
} else {
message.className = 'message right';
message.innerHTML = '密码输入正确';
}
}
</script>
</body>
</html>
页面背景替换
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
}
body {
background: url(img/bj1.jpg) no-repeat;
background-size: 100%;
}
li {
list-style: none;
}
.bj {
overflow: hidden;
margin: 100px auto;
background-color: #fff;
width: 410px;
padding-top: 3px;
}
.bj li {
float: left;
margin: 0 1px;
cursor: pointer;
}
.bj img {
width: 100px;
}
</style>
</head>
<body>
<ul class="bj">
<li>
<img src="img/bj1.jpg" alt="">
</li>
<li><img src="img/bj2.jpg" alt=""></li>
<li><img src="img/bj3.jpg" alt=""></li>
<li><img src="img/bj4.jpg" alt=""></li>
</ul>
<script>
//1.获取元素
var imgs = document.querySelector('.bj').querySelectorAll('img');
//2.循环注册事件
for (var i = 0; i < imgs.length; i++) {
imgs[i].onclick = function() {
//this.src就是我们点击图片的路径
//把这个路径给我们body的背景图路径
document.body.style.backgroundImage = 'url(' + this.src + ')';
}
}
</script>
</body>
</html>
表格隔行变色效果
//1.注册元素
var trs = document.querySelector('tbody').querySelectorAll('tr');
//2.绑定事件
for (var i = 0; i < trs.length; i++) {
//经过事件
trs[i].onmousemove = function() {
this.className = 'bg';
}
//离开事件
trs[i].onmouseout = function() {
this.className = '';
}
}
表单全选取消全选
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<style>
* {
padding: 0;
margin: 0;
}
.wrap {
width: 300px;
margin: 100px auto 0;
}
table {
border-collapse: collapse;
border-spacing: 0;
border: 1px solid #c0c0c0;
width: 300px;
}
th,
td {
border: 1px solid #d0d0d0;
color: #404060;
padding: 10px;
}
th {
background-color: #09c;
font: bold 16px "微软雅黑";
color: #fff;
}
td {
font: 14px "微软雅黑";
}
tbody tr {
background-color: #f0f0f0;
}
tbody tr:hover {
cursor: pointer;
background-color: #fafafa;
}
</style>
</head>
<body>
<div class="wrap">
<table>
<thead>
<tr>
<th>
<input type="checkbox" id="j_cbAll" />
</th>
<th>商品</th>
<th>价钱</th>
</tr>
</thead>
<tbody id="j_tb">
<tr>
<td>
<input type="checkbox" />
</td>
<td>iPhone8</td>
<td>8000</td>
</tr>
<tr>
<td>
<input type="checkbox" />
</td>
<td>iPad Pro</td>
<td>5000</td>
</tr>
<tr>
<td>
<input type="checkbox" />
</td>
<td>iPad Air</td>
<td>2000</td>
</tr>
<tr>
<td>
<input type="checkbox" />
</td>
<td>Apple Watch</td>
<td>2000</td>
</tr>
</tbody>
</table>
</div>
<script>
// 1. 全选和取消全选做法: 让下面所有复选框的checked属性(选中状态) 跟随 全选按钮即可
// 获取元素
var j_cbAll = document.getElementById('j_cbAll'); // 全选按钮
var j_tbs = document.getElementById('j_tb').getElementsByTagName('input'); // 下面所有的复选框
// 注册事件
j_cbAll.onclick = function() {
// this.checked 它可以得到当前复选框的选中状态如果是true 就是选中,如果是false 就是未选中
console.log(this.checked);
for (var i = 0; i < j_tbs.length; i++) {
j_tbs[i].checked = this.checked;
}
}
// 2. 下面复选框需要全部选中, 上面全选才能选中做法: 给下面所有复选框绑定点击事件,每次点击,都要循环查看下面所有的复选框是否有没选中的,如果有一个没选中的, 上面全选就不选中。
for (var i = 0; i < j_tbs.length; i++) {
j_tbs[i].onclick = function() {
// flag 控制全选按钮是否选中
var flag = true;
// 每次点击下面的复选框都要循环检查者4个小按钮是否全被选中
for (var i = 0; i < j_tbs.length; i++) {
if (!j_tbs[i].checked) {
flag = false;
break; // 退出for循环 这样可以提高执行效率 因为只要有一个没有选中,剩下的就无需循环判断了
}
}
j_cbAll.checked = flag;
}
}
</script>
</body>
</html>
tab栏切换
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
}
li {
list-style-type: none;
}
.tab {
width: 380px;
margin: 100px auto;
}
.tab_list {
height: 39px;
border: 1px solid #ccc;
background-color: #f1f1f1;
}
.tab_list li {
float: left;
height: 39px;
line-height: 39px;
width: 25%;
text-align: center;
cursor: pointer;
}
.tab_list .current {
background-color: #c81623;
color: #fff;
}
.item_info {
padding: 20px 0 0 20px;
}
.item {
display: none;
}
</style>
</head>
<body>
<div class="tab">
<div class="tab_list">
<ul>
<li class="current">栏目1</li>
<li>栏目2</li>
<li>栏目3</li>
<li>栏目4</li>
</ul>
</div>
<div class="tab_con">
<div class="item" style="display: block;">床前明月光</div>
<div class="item">疑是地上霜</div>
<div class="item">举头望明月</div>
<div class="item">低头思故乡</div>
</div>
</div>
<script>
//1.模块选项卡,点击某一个,当前这一个底色会是红色,其余不变(排他思想),修改类名
//获取元素
var tab_list = document.querySelector('.tab_list');
var lis = tab_list.querySelectorAll('li');
var items = document.querySelectorAll('.item');
//for循环绑定点击事件
for (var i = 0; i < lis.length; i++) {
lis[i].setAttribute('index', i);
lis[i].onclick = function () {
//先清除其余li的类
for (var i = 0; i < lis.length; i++) {
lis[i].className = '';
}
//仅留下自己
this.className = 'current';
//2.模块内容
var index = this.getAttribute('index');
//排他思想
for (var i = 0; i < items.length; i++) {
items[i].style.display = 'none';
}
items[index].style.display = 'block'
}
}
</script>
</body>
</html>
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