js編寫——輪播圖

效果圖

html頁面代碼

<!--顯示的圖片--> 
<div id="new_lunbo"> 
        <div id="list" style="left:-400px;">
      		<img src="images/lunbo(3).jpg"/>
        	<img src="images/lunbo(1).jpg"/>
         	<img src="images/lunbo(2).jpg"/>
          	<img src="images/lunbo(3).jpg"/>
         	<img src="images/lunbo(1).jpg"/>
          
        
        </div>
<!--顯示的圖片按鈕--> 
        <div id="list_nav">
         <img index="1" class="on" src="images/lunbo(1).jpg"/>
         <img index="2"  src="images/lunbo(2).jpg"/></span>
         <img index="3"  src="images/lunbo(3).jpg"/></span>
        </div>
        </div>

css格式編寫

#new_lunbo {
	float: left;
	height: 300px;
	width: 400px;
	margin-top: auto;
	margin-right: auto;
	margin-bottom: auto;
	margin-left: 14px;
	position: relative;
	overflow: hidden;
	
}
#list {
	height: 400px;
	width: 2000px;
	position: absolute;
	z-index: 1;
}
#new_lunbo #list img {
	float: left;
}
#list_nav {
	position: relative;
	margin-top:256px;
	
	z-index: 2;
	height: 44px;
	width: 400px;
}

#new_lunbo #list_nav img {
	cursor: pointer;	/*光標呈現爲指示鏈接的指針（一隻手）*/
	float: left;
	margin-top:15px;
	margin-left:15px;
	
	height: 21px;
	width: 54px;
	
}

js代碼

// JavaScript Document
window.onload = function(){
	
	 var lunbo=document.getElementById('new_lunbo');
	 var list= document.getElementById('list');
	 var list_nav=document.getElementById('list_nav').getElementsByTagName('img');
	 
		var index= 1; 
		var animated =false;
		var timer;
	 for(var i=0;i<list_nav.length;i++){
		 
		 list_nav[i].onclick = function(){
		 
		 var myIndex=parseInt(this.getAttribute('index'));
		 var offset = -400 * (myIndex-index);
		 if(!animated){
		 animate(offset);
		 }
		  index = myIndex;
		  showImgNav();
		 }
	 }
	 function showImgNav(){
		 for(var i=0;i<list_nav.length;i++){
			 if(list_nav[i].className=='on'){
				 list_nav[i].className='';
				 break;
				 }
				 }
	 	list_nav[index-1].className = 'on';
	 }
	 //顯示內容
	 function animate(offset){
		 animeted =true;
		 var newLeft=parseInt(list.style.left)+offset;
		 var time =300; //位移總時間
		 var interval =10; //位移間隔時間
		 var speed =offset/(time/interval);//每次位移量
		 function go(){
			 if((speed< 0 && parseInt(list.style.left)> newLeft) || (speed>0 && parseInt(list.style.left)< newLeft)){
		list.style.left=parseInt(list.style.left)+speed +'px'; 
		setTimeout(go,interval);//10毫秒調用一次go
		}else{
			animated = false;
			list.style.left=newLeft+'px';
		 if(newLeft>-400){
			 list.style.left = -1200+'px';
			 }
			 if(newLeft< -1200){
				list.style.left=-400+'px';
			 }
			}
			 }
		go();
		 }
		 
		 function play(){
			 
		 
			 timer = setInterval(function(){
				animate(-400);
				if(index == 3){index=1;}else{
				 index+=1;}
				 showImgNav();
				 
				 },3000);//一直執行
		 }
			 function stop(){
				 clearInterval(timer);
				 }
			lunbo.onmouseover=stop;//鼠標移動
			lunbo.onmouseout=play;
			
			play();
	 	
}

總結：我們的輪播圖其實修改了一個div中的style=left:-400;的值，動態修改它。和該div中浮動和定位overflow: hidden;