我们在日常生活中常常会看到各种各样的轮播，轮播运用的范围很广，所以我们要学会轮播。
而刚开始学轮播的时候大家都有可能碰到一个问题，那就是图片切换的不完整。比如我们点击按钮让第一张图片切换到第二张，但是第一张可能没切换完就停止切换了，所以我们要在代码运行之前就判断其他的代码是否正在运行。如图：
我们在JavaScript的开头加个判断，然后在运行代码之前再判断一下。
完整的JavaScript代码：
// JavaScript Document
var transfor=false;//记录轮播的运动状态
var index=1;
var timer=null;
window.onload=function(){var prev=document.getElementById("prev");var next=document.getElementById("next");var bottons=document.getElementById("bottons").getElementsByTagName("span");var container=document.getElementById("container");prev.onclick=function(){if(transfor==true){return;}if(index==1){index=5;}else{index--;}animate(800);showbottons();};next.onclick=function(){if(transfor==true){return;}if(index==5){index=1;}else{index++;}animate(-800);showbottons();};for(var i=0;i<bottons.length;i++){bottons[i].onclick=function(){var myindex=this.getAttribute("index");var offset=-800*(myindex-index);index=myindex;animate(offset);showbottons();};}function play(){timer=setInterval(function(){next.onclick();},2300);}function stopPlay(){clearInterval(timer);}play();container.onmousemove=stopPlay;container.onmouseout=play;
};
function animate(offset){transfor=true;var list=document.getElementById("list");var time=300;var interval=10;var speed=offset/(time/interval);var newleft=parseInt(list.style.left)+offset;
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);}else{list.style.left=newleft+"px";if(newleft>-800){list.style.left=-800*5+"px";}if(newleft<-4000){list.style.left=-800+"px";}transfor=false;}}go();}function showbottons(){var buttons=document.getElementById("bottons").getElementsByTagName("span");for(var i=0;i<buttons.length;i++){if(buttons[i].className==="on"){//buttons[i].className="";// 赋值break;}}buttons[index-1].className="on";
}源代码：
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<link rel="stylesheet" href="css/lb.css">
</head><body>
<div class="con wrap"><div class="con1"><div class="container wrap" id="container"><div class="list" id="list" style="left: -800px"><img src="./images/2.jpg" alt=""><img src="./images/1.png" alt=""><img src="./images/3.jpg" alt=""><img src="./images/4.jpg" alt=""><img src="./images/5.png" alt=""><img src="./images/2.jpg" alt=""><img src="./images/1.png" alt=""></div><div class="bottons" id="bottons"><span index="1" class="on">1</span><span index="2">2</span><span index="3">3</span><span index="4">4</span><span index="5">5</span></div><a href="javascript:void(0);" class="prev" id="prev"><</a><a href="javascript:;" class="next" id="next">></a></div></div>
</div>
<script src="js/js.js"></script>
</body>
</html>
效果图：
这样子写的话图片就可以正常切换了，你学会了吗！
