轮播图片原理 

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
  
<html>
  
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<script type="text/javascript">
 var timeID;
 var image;
 var current = 0;
 var images = new Array(4);
 function init(){
 for (var i=1;i<=4;i++){
 images[i] = new Image(450,550);
 images[i].src = "pictures/"+i+".jpg";
 }
 image = document.images[0];
 }
 function setSrc(i){
 current = i;
 //设置图片src的属性，实现图片的切换
 image.src = images[i].src;
 }
 function pre(){
 if (current <= 0){
 alert('已经是第一张了');
 }else{
 current--;
 setSrc(current);
 }
 }
 function next(){
 if (current >= 4){
 alert('已经是最后一张了');
 }else{
 current++;
 setSrc(current);
 }
 }
 function play(){
 if (current >= 4){
 current = 0;
 }
 setSrc(++current);
 }
</script>
<body onload="init()">
<input type="button" value="第一张" onclick="setSrc(1)">
<input type="button" value="上一张" onclick="pre()">
<input type="button" value="下一张" onclick="next()">
<input type="button" value="最后一张" onclick="setSrc(4)">
<input type="button" value="幻灯播放" onclick="timeID=setInterval('play()',500)">
<input type="button" value="停止播放" onclick="clearInterval(timeID)">
<div style="border:1px solid blue;width:450px; height:550px;" id="myPic">
 <img src="pictures/1.jpg" />
</div>
</body>
</html>

 

posted @ 2016-10-18 14:25  欢欢_blog  阅读(188)  评论(0)    收藏  举报