Detailed explanation of the implementation principle of js image carousel effect

Detailed explanation of the implementation principle of js image carousel effect_javascript skills

WBOY

Release： 2016-05-16 15:25:11

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The example in this article describes the implementation principle of js image carousel effect, and shares it with everyone for your reference. The specific content is as follows

<!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(5);
 function init(){
 for (var i=1;i<=5;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 >= 5){
 alert('已经是最后一张了');
 }else{
 current++;
 setSrc(current);
 }
 }
 function play(){
 if (current >= 5){
 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(5)">
<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>

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Here’s the principle

First, the init() function is used to initialize the images array and the value of the image. In this example, setSrc() is mainly used to set the src attribute value of the image, thus achieving image switching. The image carousel uses a timer. It shows when it comes! setInterval('play()',500) means calling the play() function every 0.5s!

The above is the js image carousel effect code, and a brief introduction to the principle of realizing the js image carousel effect. I hope it can help everyone to truly apply what they have learned.