js实现图片轮播

html:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<link href='style.css' rel='stylesheet' type='text/css'>
<script src='demo.js' type='text/javascript'></script>
<title>轮播图</title>
</head>
<body>
<div id='container'>
<div id='list' style='left:-120px'>
<img src='images/4.jpg'>
<img src='images/1.jpg'>
<img src='images/2.jpg'>
<img src='images/3.jpg'>
<img src='images/4.jpg'>
<img src='images/1.jpg'>
</div>
<div id='buttons'>
<span index='0' class='on'></span>
<span index='1'></span>
<span index='2'></span>
<span index='3'></span>
</div>
<div id='next' class='arrow'>&gt</div>
<div id='prev' class='arrow'>&lt</div>
</div>

</body>
</html>

*{
    margin:0;
    padding:0;
}
#buttons{
    position: absolute;
    left: 40PX;
    bottom: 5PX;
    background: #000;
    opacity: 0.5;
    border-radius: 3PX;
     40PX;
}    

#buttons span{
    margin-right: 2PX;
    cursor: pointer;
       6px;
       height:6px;
       border-radius: 50%;
       float:left;
       border:1px solid #FFF;

}


.arrow{
    cursor: pointer;
    background: #000;
    12px;
    height: 15px;
    opacity: 0.5;
    font-weight: bold;
    color:#fff;
    line-height: 15px;
    text-align: center;
    position: absolute;
    top:50px;

}

.arrow:hover{
    opacity: 0.7
}



#next{
    right:0px;
}
#prev{
    left:0px;
}




#container{
    position: relative;
    margin:150px auto;
    border: 1px solid black;
    121px;
    height:121px;
    overflow: hidden;
}


#list{
    position: absolute;
    height:120px;
    720px;
    background: red;
}
#list img{
    float:left;
}

.on{
    background: green;
}

p{
    color:green;
}

View Code

js:

window.onload=function(){
    var container=document.getElementById('container')
    var list=document.getElementById('list');
    var buttons=document.getElementById('buttons').getElementsByTagName('span');
    var next=document.getElementById('next');
    var prev=document.getElementById('prev');
    var index=0;
    var flag=false;      //设置一个布尔值，控制当画面正在动画时，不可被操作。控制是否在动画状态
    var timer;

    function move(longer){
        flag=true;         //开始动画
        //list.style.left  只能取到内嵌css的样式值
        var newleft=parseInt(list.style.left)+longer  //数值型，后面可做比较
       

       //在规定时间完成动作的函数
        var time=300;  //完成动作所需总时间
        var interval=10 //执行每个分解动作的时间间隔
        var speed=longer/(time/interval)   //距离/次数=每次移动的距离

        function go(){
            if(speed<0 && parseInt(list.style.left)>newleft || speed>0 && parseInt(list.style.left)<newleft){  //向右移动|向左移动并且没有移动至目标值时
                list.style.left=parseInt(list.style.left)+speed+'px';
                setTimeout(go,interval)        //递归
            }else{
                flag=false;  // 动画结束
                list.style.left=newleft+'px'
                if(newleft<-480){
                    list.style.left=-120+'px'
                }
                if(newleft>-120){
                    list.style.left=-480+'px'
                }
            }
        }
        go();         //调用go()函数，不然不会被执行
    }


    next.onclick=function(){
            if(index==3){                //判断语句使用双等号
                index=0
            }else{
                index+=1               
            }            
            showButton()
            if(flag==false){
                move(-120);
            }        
            
            
    }

    for(var i=0;i<buttons.length;i++){
        buttons[i].onclick=function(){
            if(this.className=="on"){
                return             //如果点击的是已经点过的图片，则跳出函数，不执行
            }
            var myindex=parseInt(this.getAttribute('index'));        //取自定义属性
            var longer=-120*(myindex-index);                    //myindex是目标的index.所有myindex-index=偏移图片量
            move(longer);
            index=myindex;          
            showButton();
        }
    }

    prev.onclick=function(){
        if(index==0){
            index=3
        }else{
            index-=1
        }            
        showButton()
        if(flag==false){
            move(120)
        }                
            
    }

    function showButton(){
         for(var i=0; i<buttons.length;i++){
             if(buttons[i].className=='on'){
                 buttons[i].className=""
             }                                     //遍历所有buttons，去掉样式”on“        
         }
        buttons[index].className='on'
     }
   
    
    function play(){
         timer=setInterval(function(){
           next.onclick()
         },3000)
     }
        
    function stop(){
         clearInterval(timer)
     }

     container.onmouseover=function(){
         stop();
     }
   
    container.onmouseout=play            //函数也可以这样调用
   
     play();           //初始状态时，执行play()
}

View Code