1、效果如下图：
2、源码如下：
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>JavaScript banner轮播 左右切换 圆点点击切换</title> <style type="text/css"> div,ul,li,a,span,img{margin:0;padding:0;} #banner { overflow:hidden; 100%; height:400px; position:relative; float:left; padding-bottom: 10px; } #tab>img:not(:first-child){ display:none; } .lunbo_btn { height: 15px; 100%; margin: 0px auto; margin-top: -40px; position: absolute; z-index: 3; text-align: center; } .lunbo_btn span { 14px; height:14px; display:inline-block; background-color:#b4b5b7; border-radius:50%; margin:0px 2px; cursor:pointer; } .lunbo_btn span.hover { background-color:#ffb23c; } .arrow { display: none; 30px; height: 60px; background-color: rgba(0,0,0,0.4); position: absolute; top: 50%; margin-top: -30px; z-index:999; } .arrow span { display: block; 10px; height: 10px; border-bottom: 2px solid #fff; border-left: 2px solid #fff; } .slider_left { margin: 25px 0 0 10px; transform: rotate(45deg); } .prve { left: 0; } .next { right: 0; } .slider_right { margin: 25px 0 0 5px; transform: rotate(-135deg); } .arrow:hover{background:#444;} #banner:hover .arrow{display:block;} </style> </head> <body> <div id="banner"> <!-- 轮播图片 --> <div id="tab"> <img class="tabImg" src="images/banner1.jpg" height="400"/> <img class="tabImg" src="images/banner2.jpg" height="400"/> <img class="tabImg" src="images/banner3.jpg" height="400"/> <img class="tabImg" src="images/banner4.jpg" height="400"/> </div> <!-- 指示符 --> <div class="lunbo_btn"> <span num="0" class="tabBtn hover"></span> <span num="1" class="tabBtn"></span> <span num="2" class="tabBtn"></span> <span num="3" class="tabBtn"></span> </div> <!-- 左右切换按钮 --> <div class="arrow prve"> <span class="slider_left"></span> </div> <div class="arrow next"> <span class="slider_right"></span> </div> </div> <script type="text/javascript"> //轮播图 var curIndex=0;//初始化 var img_number = document.getElementsByClassName('tabImg').length; var _timer = setInterval(runFn,2000);//2秒 function runFn(){ //运行定时器 curIndex = ++curIndex == img_number ? 0 : curIndex;//算法 4为banner图片数量 slideTo(curIndex); } //圆点点击切换轮播图 window.onload = function () { //为按钮初始化onclick事件 var tbs = document.getElementsByClassName("tabBtn"); for(var i=0;i<tbs.length;i++){ tbs[i].onclick = function () { clearInterval(_timer);//细节处理，关闭定时，防止点切图和定时器函数冲突 slideTo(this.attributes['num'].value); curIndex = this.attributes['num'].value _timer = setInterval(runFn,2000);//点击事件处理完成，继续开启定时轮播 } } } var prve = document.getElementsByClassName("prve"); prve[0].onclick = function () {//上一张 clearInterval(_timer);//细节处理，关闭定时，防止点切图和定时器函数冲突 curIndex--; if(curIndex == -1){ curIndex = img_number-1; } slideTo(curIndex); _timer = setInterval(runFn,2000);//点击事件处理完成，继续开启定时轮播 } var next = document.getElementsByClassName("next"); next[0].onclick = function () {//下一张 clearInterval(_timer);//细节处理，关闭定时，防止点切图和定时器函数冲突 curIndex++; if(curIndex == img_number){ curIndex =0; } slideTo(curIndex); _timer = setInterval(runFn,2000);//点击事件处理完成，继续开启定时轮播 } //切换banner图片 和 按钮样式 function slideTo(index){ console.log(index) var index = parseInt(index);//转int类型 var images = document.getElementsByClassName('tabImg'); for(var i=0;i<images.length;i++){//遍历每个图片 if( i == index ){ images[i].style.display = 'inline';//显示 }else{ images[i].style.display = 'none';//隐藏 } } var tabBtn = document.getElementsByClassName('tabBtn'); for(var j=0;j<tabBtn.length;j++){//遍历每个按钮 if( j == index ){ tabBtn[j].classList.add("hover"); //添加轮播按钮hover样式 curIndex=j; }else{ tabBtn[j].classList.remove("hover");//去除轮播按钮hover样式 } } } </script> </body> </html>
完毕！
good job! good luck!