简单实现js轮播图效果

时间：2021-05-18

本文实例为大家分享了js实现轮播图效果展示的具体代码，供大家参考，具体内容如下

html结构

<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Document</title> <style> *{ margin:0; padding:0; font-size:14px; -webkit-user-select:none; } ul,li{ list-style:none; } img{ display:block; border:none; } a{ display:block; color:#000; text-decoration: none; } a:hover,a:active,a:visited,a:target{ display:block; color:#000; text-decoration: none; } .banner{ position:relative; margin:0 auto; width:1000px; height:300px; overflow:hidden; } .banner .inner{ position:absolute; top:0; left:0; height:300px; width:1000px; } .banner .inner div{ float:left; width:1000px; height:300px; background:url('img/default.gif') no-repeat center center #e1e1e1; } .banner .inner img{ display:none; width:100%; height:100%; opacity:0; filter:alpha(opacity=0); } .banner .bannerTip{ height:18px; position:absolute; right:20px; bottom:20px; } .banner .bannerTip li{ float:left; margin-left:10px; width:18px; height:18px; border-radius:50%; background:lightblue; cursor:pointer; } .banner .bannerTip li.bg{ background:red; } .banner a{ display:none; position:absolute; top:50%; margin-top:-22.5px; width:30px; height:45px; background-image:url("img/pre.png"); background-repeat:no-repeat; opacity:0.5; filter:alpha(opacity=50); } .banner a:hover{ opacity:1; filter:alpha(opacity=100); } .banner a.bannerLeft{ left:20px; background-position:0 0; } .banner a.bannerRight{ right:20px; background-position:-45px 0; } </style></head><body> <div class='banner' id='banner'> <div class='inner'> <div><img src="img/banner1.jpg" alt=""></div> <div><img src="img/banner2.jpg" alt=""></div> <div><img src="img/banner3.jpg" alt=""></div> <div><img src="img/banner4.jpg" alt=""></div> </div> <ul class='bannerTip'> <li class='bg'></li> <li></li> <li></li> <li></li> </ul> <a href="javascript:;" class='bannerLeft'></a> <a href="javascript:;" class='bannerRight'></a> </div></body></html>

js

(function(){ var banner = document.getElementById('banner'); var bannerInner = utils.firstChild(banner); var bannerTip = utils.children(banner,'ul')[0]; var imgList = bannerInner.getElementsByTagName('img'); var oLis = bannerTip.getElementsByTagName('li'); var bannerLeft = utils.children(banner,'a')[0]; var bannerRight = utils.children(banner,'a')[1]; //实现数据绑定：Ajax请求数据、按照字符串拼接的方式绑定数据 var jsonData = null,count = null ~function(){ var xhr = new XMLHttlRequest; xhr.open('get',"json/banner.txt?_="+Math.random(),false); xhr.onreadystatechange = function(){ if(xhr.readyState === 4 && /^2\d{2}$/.test(xhr.status)){ jsonData = utils.formatJSON(xhr.responseText); } } xhr.send(null); }() ~function(){ //绑定轮播图区域的数据 var str = ""; if(jsonData){ for(var i = 0,len = jsonData.length;i<len;i++){ str+='<div><img src="" trueImg="'+jsonData[i]['img']+'"></div>' } //为了实现无缝滚动，需要把第一张克隆一份放在末尾 str+= '<div><img src="" trueImg="'+jsonData[0]['img']+'"></div>' } bannerInner.innerHTML = str; count = jsonData.length+1; utils.css(bannerInner,"width",count*1000); //绑定焦点区域的数据 str = ''; if(jsonData){ for(var i = 0,len = jsonData.length;i<len;i++){ i===0?str+='<li class="bg"></li>':str+='<li></li>'; } } bannerTip.innerHTML = str; }() //图片延迟加载 function lazyImg(){ for(var i = 0,len = imgList.length;i<len;i++){ ~function(i){//这里使用闭包，来避免onload事件异步导致的只有最后一张图片延迟加载的问题 var curImg = imgList[i]; var oImg = new Image; oImg.src = curImg.getAttribute('trueImg'); oImg.onload = function(){ curImg.src = this.src; curImg.style.display = "block"; oImg = null; myAnimate(curImg,{opacity:1},300) } }(i) } } window.setTimeout(lazyImg,500); var step = 0;//记录的是步长，（当前是哪一张图片，0是第一张图片） //实现自动轮播 var autoTimer = window.setInterval(autoMove,2000); function autoMove(){ if(step===count-1){ step =0; bannerInner.style.left = 0 } step++; myAnimate(bannerInner,{left:-step*1000},500) changeTip(); } //实现焦点对齐 function changeTip(){ var tempStep = step > oLis.length-1 ? 0 : step; for(var i = 0,len = oLis.length;i<len;i++){ var curLi = oLis[i]; i === tempStep ? utils.addClass(curLi,"bg") : utils.removeClass(curLi,"bg") } } //鼠标滑过停止和开启轮播 banner.onmouseover = function(){ window.clearInterval(autoTimer); bannerLeft.style.display = bannerRight.style.display = 'block'; } banner.onmouseout = function(){ autoTimer = window.setInterval(autoTimer,2000); bannerLeft.style.display = bannerRight.style.display = 'none'; } //点击焦点实现轮播图的切换 ~function(){ for(var i = 0,len = oLis.length;i<len;i++){ var curLi = oLis[i]; curLi.index = i; curLi.onclick = function(){ step = this.index; changeTip(); myAnimate(bannerInner,{left:-step*1000},500) } } }() //实现左右切换 bannerRight.onclick = autoMove(); bannerLeft.onclick = function(){ if(step<=0){ step = count-1; utils.css(bannerInner,"left",-step*1000); } step--; autoMove(); }})()

绑定的数据

[ {"img":"img/banner1.jpg","desc":"第一张轮播图"}, {"img":"img/banner2.jpg","desc":"第二张轮播图"}, {"img":"img/banner3.jpg","desc":"第三张轮播图"}, {"img":"img/banner4.jpg","desc":"第四张轮播图"}]

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。

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