第四章 JS特效

第四章 JS特效

01.图片切换

效果图如下：

html代码如下：

<img src="images/image01.jpg" id="flower" width="200" height="200">
<br>
<button id="prev">上一张</button>
<button id="next">下一张</button>

javascript代码如下：

// 1.获取事件源 需要的标签
var flower = document.getElementById('flower');
var nextBtn = document.getElementById('next');
var prevBtn  = document.getElementById('prev');
var minIndex = 1,maxIndex = 4; currentIndex = minIndex;
// 2.监听按钮的点击
nextBtn.onclick = function(){
if(currentIndex === maxIndex){
    // 到最后一张了
    currentIndex = minIndex;
    }else{
    currentIndex++;
    }
    flower.setAttribute('src',`images/image0${currentIndex}.jpg`)
}
prevBtn.onclick = function(){
    if(currentIndex === minIndex){
            // 到最后一张了
            currentIndex = maxIndex;
     }else{
            currentIndex--;
     }
     flower.setAttribute('src',`images/image0${currentIndex}.jpg`)
}

02.显示和隐藏图片

效果图如下：

html代码如下：

<button id="btn">隐藏</button>
<br>
<img src="images/img01.jpg" id="new">

javascript代码如下：

// 1.获取事件源
var obtn = document.getElementById('btn');
var newImg = document.getElementsByTagName('img')[0];
// var isShow = true;
// 2.绑定事件
obtn.onclick = function(){
    // 3.事件驱动程序
    if(obtn.innerHTML === '隐藏'){
        newImg.style.display = 'none';
        obtn.innerHTML = '显示';
        // isShow = false;
     }else{
         newImg.style.display = 'block';
        obtn.innerHTML = '隐藏';
        // isShow = true;
     }
}

03.衣服相册

效果图如下：

css代码如下：

<style type="text/css">
    *{
        padding: 0;
        margin: 0;
    }
    ul{
        list-style: none;
        overflow: hidden;
    }
    ul li{
        float: left;
        width: 50px;
        height: 50px;
        margin-left: 10px;
        margin-top: 20px;
        border: 2px solid #fff;
    }
    ul li.active{
        border-color: red;
    }
 </style>

html代码如下：

<img src="images/1.jpg" id="bigImg">
<ul>
    <li class="active">
        <a href="">
        <img src="images/1.jpg" width="46"  class="smallImg">
        </a>
    </li>
    <li>
        <a href="">
        <img src="images/2.jpg" width="46" class="smallImg">
        </a>
    </li>
    <li>
        <a href="">
        <img src="images/3.jpg" width="46" class="smallImg">
        </a>
    </li>
    <li>
        <a href="">
        <img src="images/4.jpg" width="46" class="smallImg">
        </a>
    </li>
    <li>
        <a href="">
        <img src="images/5.jpg" width="46" class="smallImg">
        </a>
    </li>
</ul>

javascript代码如下：

// 1.获取事件源
var bigImg  = document.getElementById('bigImg');
var smallImgs  = document.getElementsByClassName('smallImg');
for(var i = 0; i < smallImgs.length; i++){
    //2. 遍历集合，给每个img标签添加事件
    smallImgs[i].onmouseover = function(){
    // 3.事件处理程序
    // 3.1 在悬浮到每个li标签之前，先把所有的li标签的类名都置为空值
    for(var j = 0; j < smallImgs.length; j++){
        smallImgs[j].parentNode.parentNode.setAttribute('class', '');
    }
    // 3.2修改大图的src属性值
    var smallImgSrc = this.getAttribute('src');
    bigImg.setAttribute('src',smallImgSrc);
    // 3.3 给鼠标悬浮的img标签的父标签添加类
    this.parentNode.parentNode.setAttribute('class', 'active');
    }
}

04.关闭小广告

效果图如下：

css代码如下：

<style type="text/css">
    *{
        padding: 0;
        margin: 0;
     }
     #qe_code{
         width: 180px;
         height: 160px;
         margin: 100px auto;
         position: relative;
     }
     #qe_code img{
         position: absolute;
         right: 0;
     }
     #qe_code #close{
         position: absolute;
         width: 18px;
         height: 18px;
         border: 1px solid #e0e0e0;
         text-align: center;
         line-height: 18px;
         cursor: pointer;
         color: #666;
     }
</style>

html代码如下：

<div id="qe_code">
    <img src="images/phone_taobao.png" id="code">
    <span id="close">X</span>
</div>

javascript代码如下：

var closeSpan = document.getElementById('close');
var qe_code = document.getElementById('qe_code');
    closeSpan.onclick = function(){
        qe_code.style.display = 'none';
    }

05.图片切换

效果图如下：

css代码如下：

<style type="text/css">
    *{
        padding: 0;
        margin: 0;
     }
     #box{
         border: 1px solid #ccc;
         width: 430px;
         height: 70px;
         padding-top: 430px;
         background: url('images/big_pic1.jpg') no-repeat;
     }
     #box ul li{
         display: inline-block;
         margin-right: 15px;
     }
</style>

html代码如下：

<div id="box">
    <ul>
        <li id="item1" class="item">
            <img src="images/pic1.jpg">
        </li>
        <li id="item2" class="item">
            <img src="images/pic2.jpg">
        </li>
        <li id="item3" class="item">
            <img src="images/pic3.jpg">
        </li>
        <li id="item4" class="item">
            <img src="images/pic4.jpg">
        </li>
        <li id="item5" class="item">
            <img src="images/pic5.jpg">
        </li>
    </ul>
</div>

javascript代码如下：

// 初学者 小白 书写的方式
// 1.获取事件源
/*
var item1 = document.getElementById('item1');
var item2 = document.getElementById('item2');
var item3 = document.getElementById('item3');
var item4 = document.getElementById('item4');
var item5 = document.getElementById('item5');
var oBox = document.getElementById('box');
$('item1').onmouseover = function(){
    oBox.style.background = `url('images/big_pic1.jpg') no-repeat`
}
$('item2').onmouseover = function(){
    oBox.style.background = `url('images/big_pic2.jpg') no-repeat`
}
$('item3').onmouseover = function(){
    oBox.style.background = `url('images/big_pic3.jpg') no-repeat`
}
$('item4').onmouseover = function(){
    oBox.style.background = `url('images/big_pic4.jpg') no-repeat`
}
$('item5').onmouseover = function(){
    oBox.style.background = `url('images/big_pic5.jpg') no-repeat`
}
*/
//封装代码1如下：
// 1.获取事件源
function $(id){
    return typeof id === 'string' ? document.getElementById(id) : null;
}
function changebgcImg(liId,imgSrc){
    // 2.添加事件
    $(liId).onmouseover = function(){
        // 3.改变背景图
        $('box').style.background = imgSrc;
    }
}
changebgcImg('item1',`url('images/big_pic1.jpg') no-repeat`);
changebgcImg('item2',`url('images/big_pic2.jpg') no-repeat`);
changebgcImg('item3',`url('images/big_pic3.jpg') no-repeat`);
changebgcImg('item4',`url('images/big_pic4.jpg') no-repeat`);
changebgcImg('item5',`url('images/big_pic5.jpg') no-repeat`);
//封装代码2如下：
// 1.获取事件源
function $(id){
    return typeof id === 'string' ? document.getElementById(id) : null;
}
var items = document.getElementsByClassName('item');
for(var i = 0;i < items.length; i++){
    var item  = items[i];
    item.index = i+1;
    items[i].onmouseover = function(){
        $('box').style.background = ` url('images/big_pic${this.index}.jpg') no-repeat`;
    }
}

06.百度换肤

效果图如下：

css代码如下：

<style type="text/css">
    *{
        margin:0px;
        padding:0px;
     }
     ul{
        list-style:none;
     }                          
     #skin{
        position:fixed;
        top:0px;
        left:0px;
        width:100%;
        height:100%;
        backgroundimage:url('images/skin1.jpg');
        background-position:center 0;
        background-repeat:no-repeat;
     }
     #skin-photo{
        width:100%;
        height:100px;
        position:relative;
        z-index:10;
     }
     #skin-photo ul{
        overflow:hidden;
        width:1200px;
        margin:0 auto;
        background-color:rgba(255,255,255,0.5)
     }
    #skin-photo ul li{
        float:left;
        cursor:pointer;
        height:120px;
        margin:10px 0 10px 96px;
    }
    #skin-photo ul li img{
        width:180px;
        height:120px;
    }
</style>

html代码如下：

<div id="skin"></div>
<div id="skin-photo">
    <ul>
        <li>
            <img src="images/skin1.jpg" id="0">
        </li>
        <li>
            <img src="images/skin2.jpg" id="1">
        </li>
        <li>
            <img src="images/skin3.jpg" id="2">
        </li>
        <li>
            <img src="images/skin4.jpg" id="3">
        </li>
    </ul>
</div>

javascript代码如下：

![07](C:\Users\静静\Desktop\1111\pic\07.png)![07](C:\Users\静静\Desktop\1111\pic\07.png)//1.获取对应的图片
var skin = document.getElementById('skin');
var allItems = document.getElementsByTagName('li');
console.log(allItems);
    for(var i=0;i<allItems.length;i++){     
        allItems[i].index =i+1;
        allItems[i].onclick =function(){
        skin.style.backgroundImage=`url(images/skin${this.index}.jpg)`;
    }
}

07.千千音乐盒

效果图如下：

css代码如下：

<style type="text/css">
    *{
        padding:0px;
        margin:0px;
    }
    #panel{
        background-color:#fff;
        border:1px solid #ddd;
        border-radius:4px;
        width:400px;
        padding:20px;
        margin:100px auto;
    }
    .panel-footer{
           text-align:center;
    } 
    .panel-footer button{
        margin-left:20px;
        margin-top:20px;
    }
</style>

html代码如下：

<div id="panel">
    <div class="panel-title">
        <h3>千千音乐盒</h3>
        <hr>
    </div>
    <div class="panel-content">
        <input type="checkbox">漂洋过海来看你<br>
        <input type="checkbox">一眼万年<br>
        <input type="checkbox">后来<br>
        <input type="checkbox">没那么简单<br>
        <input type="checkbox">如果你要离去<br>
        <input type="checkbox">恋恋风尘<br>
        <input type="checkbox">南山南<br>
        <input type="checkbox">涛声依旧<br>
        <input type="checkbox">可惜不是你<br>           
    </div>
    <div class="panel-footer">
        <hr>
        <button id="allSelect">全选</button>
        <button id="cancelSelect">取消选中</button>
        <button id="reverseSelect">反选</button>
    </div>
</div>

javascript代码如下：

function $(id){
    return typeof id === 'string'?document.getElementById(id):null;
}
//1.获取所有的复选框
var inputs = document.getElementsByTagName('input');
//2.全选
$('allSelect').onclick = function(){
    for(var i=0;i<inputs.length;i++){
        inputs[i].checked = true;
    }
}
//3.取消选中
$('cancelSelect').onclick = function(){
    for(var i=0;i<inputs.length;i++){
        inputs[i].checked = false;
    }
}
//4.反选
$('reverseSelect').onclick = function(){
    for(var i=0;i<inputs.length;i++){
        // if(inputs[i].checked){
        //     inputs[i].checked = false;
        // }else{
        //     inputs[i].checked = true;
        // }
        inputs[i].checked = !inputs[i].checked;
    }
}

08.表单验证

效果图如下：

css代码如下：

<style type="text/css">
    *{
        padding:0px;
        margin:0px;
    }
    #prompt{
        font-size:12px;
        color:darkgray;
    }
    #score{
        border:1px solid darkgray;
    }
    .right{
        background:url('images/right.png') no-repeat 5px center;
        padding-left:20px;
        color:lightgreen !important;
        background-size:15px 15px;
    }
    .error{
        background:url('images/error.png') no-repeat 5px center;
        padding-left:20px;
        color:red !important;
        background-size:15px 15px;
    }
</style>

html代码如下：

<div id="box">
    <label for="score">你的成绩：</label>
    <input type="text" placeholder="请输入分数" id="score">
    <span id="prompt">请输入您的成绩！</span>
</div>

javascript代码如下：

![09](C:\Users\静静\Desktop\1111\pic\09.png)![09](C:\Users\静静\Desktop\1111\pic\09.png)function $(id){
    return typeof id === 'string'?document.getElementById(id):null;
}
//input输入框失去焦点
$('score').onblur = function(){
    //1获取输入的内容
    var value = parseFloat(this.value);
    console.log(typeof value);
    //2.验证
    console.log(isNaN(value));
    if(isNaN(value)){
        //不是一个数
        $('prompt').innerHTML = '输入的成绩不正确';
        // $('prompt').setAttribute('class','error');
        $('prompt').className = 'error';
        this.style.borderColor = 'red';
        }else if(value>0 && value<=100){
        $('prompt').innerHTML = '输入的成绩正确';
        // $('prompt').setAttribute('class','error');
        $('prompt').className = 'right';
        this.style.borderColor = 'green';
    }else{
        //超出成绩范围
        $('prompt').innerHTML = '输入的成绩正确必须0-100';
        // $('prompt').setAttribute('class','error');
        $('prompt').className = 'error';
        this.style.borderColor = 'red';
    }
}
//input输入框获取焦点 恢复原来的状态
$('score').onfocus = function(){
    $('prompt').innerHTML = '请输入您的成绩！';
    $('prompt').className = '';
    $('score').style.borderColor = 'darkgrey';
    $('score').style.outline = 'none';
    $('score').value = '';
}

09.上传图片验证

效果图如下：

html代码如下：

<label for="file">上传图片格式验证：</label>
<input type="file" name="" id="file">

javascript代码如下：

//jpg png gif 
window.onload = function(){
    //1.获取标签
    var file = document.getElementById('file');
    //2.监听图片选择变化
    file.onchange = function(){
        //2.1获取上传的图片路径
        var path = this.value;
        // console.log(path);//C:\fakepath\an1.png
        //2.2获取在路径字符串中占的位置
        var loc = path.lastIndexOf('.');
        //2.3截图文件路径的后缀名
        var suffix = path.substr(loc);
        //2.4统一转小写
        var lower_suffix = suffix.toLowerCase();
        //2.5判断
        if(lower_suffix === '.jpg' || lower_suffix === '.png'|| lower_suffix === '.jpeg'|| lower_suffix             === '.gif'){
            alert('上传图片格式正确');
         }else{
             alert('上传图片格式错误');
         }
     }
 }

10.随机验证码校验

效果图如下：

css代码如下：

#code{
    width:100px;
    height:100px;
    background-color:#ddd;
    padding:10px;
    line-height:100px;
    text-align:center;
    font-size:20px;
    color:red;
    font-weight:bold;
}
input{outline:none;}

html代码如下：

<div id="code"></div>
<input type="text" id="newCode">
<input type="button" id="validate" value="验证">

javascript代码如下：

window.onload = function(){
    //设置默认空的字符串
    var code;
    var codeDiv = document.getElementById('code');
    var newCodeInput = document.getElementById('newCode');
    var validate = document.getElementById('validate');
    //加载页面对应的验证码
    createCode();
    //1.获取min到max之间的整数(1-100)
    function random(max,min){
        return Math.floor(Math.random()*(max-min)+min);
    }
    function createCode(){
        code = '';
        //设置长度;
        var codeLength = 4;
        var randomCode = [0,1,2,3,4,5,6,7,8,9,'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'];
        for(var i = 0;i < codeLength; i++){
                //设置随机范围0~36
                var index = random(0,62);
                code += randomCode[index];
            }
            codeDiv.innerHTML = code;
        }
    //验证按钮校验
    validate.onclick = function(){
        //获取用户新输入的验证码
        var newCode = newCodeInput.value;
        // var newCode = newCodeInput.value.toUpperCase();
        if(newCode === code){
            //验证成功跳转网址
            window.location.href = 'http://php.cn';
        }else{
            //验证失败
            alert('输入验证码错误,请重新输入');
            //输入框中的值为空
            newCodeInput.value = '';
            //重新生成验证码
            createCode();
        }
    }
}

11.发布评论

效果图如下：

css代码如下：

<style type="text/css">
    *{padding:0px;margin:0px;}
    ul{list-style:none;}
    #box{width:1000px;border:1px solid #ccc;margin:100px auto;padding:20px;}
    #comment{width:80%;padding:10px 10px;font-size:20px;outline:none;}
    .box_top{margin-bottom:20px;}
    #comment_content li{border-bottom:1px dashed #ccc;width:800px;color:red;line-height:45px;}
    #comment_content li a{float:right;}
</style>

html代码如下：

<div id="box">
    <div class="box_top">
        <textarea  id="comment" cols="100" rows="10" placeholder="请输入你的评论"></textarea>
        <button id="btn">发布</button>
    </div>
        <!-- javascript:void(0); 禁用a链接本身事件 -->    
</div>

javascript代码如下：

window.onload = function(){
    //1.监听按钮的点击
    $('btn').onclick = function(){
        //1.1获取用户输入的内容
        var content = $('comment').value;
        console.log(content);
        //1.2判断
        if(content.length === 0){
            alert('请输入内容');
            return;
         }
         //1.3创建li标签插入到ul中
         var newLi = document.createElement('li');
         newLi.innerHTML = `${content}<a href='javascript:void(0)'>删除</a>`;
         // $('comment_content').appendChild(newLi);
         $('comment_content').insertBefore(newLi,$('comment_content').children[0]);
         //1.4清空输入框中的内容
         $('comment').value='';
         //1.5删除评论
         var delBtns = document.getElementsByTagName('a');
         for(var i=0;i<delBtns.length;i++){
             delBtns[i].onclick = function(){
                this.parentNode.remove();
              }
         }
     }
    function $(id){
        return typeof id === 'string'?document.getElementById(id):null;
    }
}

12.九宫格布局

效果图如下：

css代码如下：

1.浮动写法：
*{margin:0px;padding:0px;}
#wrap{overflow:hidden;}
#wrap .item{width:248px;height:360px;font-size:13px;}
#wrap .item .title{width:248px;height:30px;line-height:30px;overflow:hidden;margin-bottom:10px;}
.imgContainer{width:248px;display:table-cell;text-align:center;}
#wrap .item .price{color:#ff6700;font-size:18px;font-weight:bold;}
2.定位写法：
 *{margin:0px;padding:0px;}
 #wrap{position:relative;}
 #wrap .item{width:248px;height:360px;font-size:13px;}
 #wrap .item .title{width:248px;height:30px;line-height:30px;overflow:hidden;margin-bottom:10px;}
 .imgContainer{width:248px;display:table-cell;text-align:center;}
 #wrap .item .price{color:#ff6700;font-size:18px;font-weight:bold;}

html代码如下：

<div class="cols">
    <button>3列</button>
    <button>4列</button>
    <button>5列</button>
</div>
<div id="wrap">
    <div class="item">
        <div class="imgContainer">
            <img src="images/taobao_1.jpg">
        </div>
        <p class="title">纯色短袖女春季秋t恤韩版国新款复制2019潮</p>
        <p class="price">￥69</p>
    </div>
    <div class="item">
        <div class="imgContainer">
            <img src="images/taobao_2.jpg">
        </div>
        <p class="title">纯色短袖女春季秋t恤韩版国新款复制2019潮</p>
        <p class="price">￥110</p>
    </div>
    <div class="item">
        <div class="imgContainer">
            <img src="images/taobao_3.jpg">
        </div>
        <p class="title">纯色短袖女春季秋t恤韩版国新款复制2019潮</p>
        <p class="price">￥169</p>
    </div>
    <div class="item">
        <div class="imgContainer">
            <img src="images/taobao_4.jpg">
        </div>
        <p class="title">纯色短袖女春季秋t恤韩版国新款复制2019潮</p>
        <p class="price">￥349</p>
    </div>
    <div class="item">
        <div class="imgContainer">
            <img src="images/taobao_5.jpg">
        </div>
        <p class="title">纯色短袖女春季秋t恤韩版国新款复制2019潮</p>
        <p class="price">￥56</p>
    </div>
    <div class="item">
        <div class="imgContainer">
            <img src="images/taobao_6.jpg">
        </div>
        <p class="title">纯色短袖女春季秋t恤韩版国新款复制2019潮</p>
        <p class="price">￥89</p>
    </div>
    <div class="item">
        <div class="imgContainer">
            <img src="images/taobao_7.jpg">
        </div>
        <p class="title">纯色短袖女春季秋t恤韩版国新款复制2019潮</p>
        <p class="price">￥99</p>
    </div>
    <div class="item">
        <div class="imgContainer">
            <img src="images/taobao_8.jpg">
        </div>
        <p class="title">纯色短袖女春季秋t恤韩版国新款复制2019潮</p>
        <p class="price">￥98</p>
    </div>
    <div class="item">
        <div class="imgContainer">
            <img src="images/taobao_9.jpg">
        </div>
        <p class="title">纯色短袖女春季秋t恤韩版国新款复制2019潮</p>
        <p class="price">￥68</p>
    </div>
    <div class="item">
        <div class="imgContainer">
            <img src="images/taobao_10.jpg">
        </div>
        <p class="title">纯色短袖女春季秋t恤韩版国新款复制2019潮</p>
        <p class="price">￥45</p>
    </div>
    <div class="item">
        <div class="imgContainer">
            <img src="images/taobao_11.jpg">
        </div>
        <p class="title">纯色短袖女春季秋t恤韩版国新款复制2019潮</p>
        <p class="price">￥78</p>
    </div>
    <div class="item">
        <div class="imgContainer">
            <img src="images/taobao_12.jpg">
        </div>
        <p class="title">纯色短袖女春季秋t恤韩版国新款复制2019潮</p>
        <p class="price">￥89</p>
    </div>
    <div class="item">
        <div class="imgContainer">
            <img src="images/taobao_13.jpg">
        </div>
        <p class="title">纯色短袖女春季秋t恤韩版国新款复制2019潮</p>
        <p class="price">￥47</p>
    </div>
</div>

javascript代码如下：

1.浮动写法：
//1.获取标签
var btns = document.getElementsByTagName('button');
var items = document.getElementsByClassName('item');
//2.监听按钮的点击
btns[0].onclick = function(){
    lj_flex(3);          
}
btns[1].onclick = function(){
    lj_flex(4);          
}
btns[2].onclick = function(){
    lj_flex(5);          
}
function lj_flex(colNum){
    //3.循环
    for(var i=0;i<items.length;i++){
        // var itemW = 248;
        items[i].style.float='left';
        // console.log(items[i].offsetWidth);
        items[i].parentNode.style.width = (colNum*items[i].offsetWidth) + 'px';
    }
}
2.定位写法：
//1.获取标签
var btns = document.getElementsByTagName('button');
var items = document.getElementsByClassName('item');
//2.监听按钮的点击
btns[0].onclick = function(){
    lj_flex(3);          
}
btns[1].onclick = function(){
    lj_flex(4);          
}
btns[2].onclick = function(){
    lj_flex(5);          
}
function lj_flex(colsNum){
    //第0行第0列 top:0*h left:0*h
    //第0行第1列 top:0*h left:1*h
    //第0行第2列 top:0*h left:2*h
    //第1行第0列 top:1*h left:0*h
    //第1行第1列 top:1*h left:1*h
    //第1行第2列 top:1*h left:2*h
    //第2行第0列 top:2*h left:0*h
    //第2行第1列 top:2*h left:1*h
    //第2行第2列 top:2*h left:2*h
    for(var i=0;i<items.length;i++){
        //求每个盒子占的行数和列数
        var row = parseInt(i/colsNum);
        var col = parseInt(i%colsNum);
        //设置盒子定位
        items[i].style.position = 'absolute';
        items[i].style.top = (row*items[i].offsetHeight)+'px';
        items[i].style.left = (col*items[i].offsetWidth)+'px';
}

13.日期特效

效果图如下：

css代码如下：

*{margin:0px;padding:0px;}
#date{width:450px;height:300px;background-color:darkorange;border-radius:10px;margin:100px auto;}
#nowDate{width:450px;height:60px;line-height:60px;text-align:center;color:#fff;font-size:26px;}
#day{width:200px;height:200px;line-height:200px;background-color:orchid;margin:0px auto;text-align:center;color:#fff;font-weight:bold;font-size:60px;}

html代码如下：

<div id="date">
    <p id="nowDate"></p>
    <p id="day"></p>
</div>

javascript代码如下：

//1.获取标签
var nowDate = document.getElementById('nowDate');
var days = document.getElementById('day');
//用定时器更新时间的变化
setInterval(nowTime,100);
// nowDate.innerHTML= '';
function nowTime(){
    //0-23;
    //6:27:35 P.M.
    //6:30:01 P.M.
    //6:04:01 A.M.
    var now = new Date();
    var hour = now.getHours();//时
    var minute = now.getMinutes();//分
    var second = now.getSeconds();//秒
    var year = now.getFullYear();//年
    var month = now.getMonth();//月
    var day = now.getDate();//日
    var week = now.getDay();//星期
    // console.log(week);//索引
    var weeks=['星期天','星期一','星期二','星期三','星期四','星期五'];
    //18>12?(18-12):8
    var temp ='' + (hour > 12 ? hour - 12 : hour);
    if(hour === 0){
    temp = '12';
    }else if(hour < 10 && hour != 10){
    temp = '0' + temp;
    }
    temp = temp + (minute < 10 ? ':0' : ":") + minute;
    temp = temp + (second < 10 ? ':0' : ":") + second;
    temp = temp + (hour >= 12 ? ' P.M.' : ' A.M.');
    temp = `${year}年${month}月${day}日${temp}${weeks[week]}`;
    nowDate.innerHTML = temp;
    days.innerHTML = day;
}

14.定时器的回顾和transform的应用

css代码如下：

#box{
    width:50px;
    height:50px;
    background-color:red;
    /* transform:translate(100px,200px)rotate(50deg)scale(2.0)skew(10deg); */
    /* translate:位移;rotate:旋转;scale:放大;skew:倾斜; */
}

html代码如下

<button id="start">开启</button>
<button id="stop">关闭</button>
<button id="btn">形变</button>
<div id="box"></div>

javascript代码如下：

//1.获取标签
var start = document.getElementById('start');
var stop = document.getElementById('stop');
var num = 0,timer = null;
start.onclick = function(){
        //使用定时器的时候先清除定时器再开启定时器，防止用户频繁性的开启定时器
        clearInterval(timer);
        timer = setInterval(function(){
            num++;
            console.log(num);
        },1000)
    }
stop.onclick = function(){
    clearInterval(timer);
}
window.onload = function(){
    var btn = document.getElementById('btn');
    var box = document.getElementById('box');
    var index = 0;
    btn.onclick = function(){
    index++;
    box.style.transform =   `translate(${index*100}px,${index*50}px)rotate(${index*10}deg)scale(${index*1.3})`;
    }
}

15.数字时钟案例

效果图如下：

css代码如下：

<style type="text/css">
    *{padding:0px;margin:0px;}
    #clock{width:600px;height:600px;background:url('images/clock.jpg')no-repeat;position:relative;}
    #hour,#minute,#second{position:absolute;width:30px;height:600px;left:50%;top:0;margin-left:-15px;}
    #hour{background:url(images/hour.png)no-repeat center center;}
    #minute{background:url(images/minute.png)no-repeat center center;}
    #second{background:url(images/second.png)no-repeat center center;}
</style>

html代码如下：

<div id="clock">
    <div id="hour"></div>
    <div id="minute"></div>
    <div id="second"></div>
</div>

javascript代码如下：

//1.获取标签
var hour = document.getElementById('hour');
var minute = document.getElementById('minute');
var second = document.getElementById('second');
//2.开启定时器获取当前时间
setInterval(function(){
    //2.1获取当前的时间戳
    var now =new Date();
    //2.2获取小时 分钟 秒
    var sec = now.getSeconds();
    var min = now.getMinutes()+sec/60;
    var hou = now.getHours()%12+min/60;
    //2.3旋转
    second.style.transform =`rotate(${sec*6}deg)`;
    minute.style.transform =`rotate(${min*6}deg)`;
    hour.style.transform =`rotate(${hou*30}deg)`;
},10)

16.长图滚动案例

效果如下：

css代码如下：

<style type="text/css">
*{padding:0px;margin:0px;}
body{background-color:#000;}
#box{width:658px;height:400px;border:1px solid #ff6700;margin:100px auto;overflow:hidden;position:relative;}
#box img{position: absolute;top:0px;left:0px;}
#box span{position:absolute;width:100%;height:50%;left:0px;cursor:pointer;}
#box #top{top:0px;}
#box #bottom{bottom:0px;}
</style>

html代码如下：

<div id="box">
    <!-- 658*4066 -->
    <img src="images/timer.jpeg" alt="">
    <span id="top"></span>
    <span id="bottom"></span>
</div>

javascript代码如下：

//1.获取标签
var box =document.getElementById('box');
var pic =document.getElementsByTagName('img')[0];
var divTop =document.getElementById('top');
var divBottom = document.getElementById('bottom');
var num = 0;
var timer = null;
divTop.onmouseover = function(){
    //让图片向上滚动
    clearInterval(timer);
    timer = setInterval(function(){
    num-=10;      
    if(num>=-3666){
        pic.style.top = num+'px';//4066-400=3666
    }else{
        clearInterval(timer);
    }
    },50);
}
divBottom.onmouseover  = function(){
    clearInterval(timer);
    //  让图片向上滚动
    timer = setInterval(function(){
        num += 10;
        if(num <= 0){
            pic.style.top = num + 'px'; 
        }else{
            clearInterval(timer);
        }
    },100);
}
box.onmouseout = function(){
    clearInterval(timer);
}