本文實例講述了JS實現圖片輪播效果。分享給大家供大家參考，具體如下：
本次輪播效果圖如下：
具有以下功能：1.自動播放（鼠標進入顯示區域時停止播放） 2.左右焦點切換 3.底下小按鈕切換
以下為實現代碼：
首先是html代碼：
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>最簡單的輪播效果</title></head><body><div class="box" id="box"> <div class="inner"> <!--輪播圖--> <ul> <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/1.jpg" <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/2.jpg" <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/3.jpg" <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/4.jpg" <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/5.jpg" </ul> <ol class="bar"> 小按鈕數量無法確定，由js動態生成 </ol> <!--左右焦點--> <div id="arr"> <span id="left"> <</span> <span id="right">></span> </div> </div></div></body></html>
接下來是css樣式：
<style> * { margin: 0; padding: 0 } .box { width: 500px; height: 300px; border: 1px solid #ccc; margin: 100px auto; padding: 5px; } .inner{ width: 500px; height: 300px; position: relative; overflow: hidden; } .inner img{ width: 500px; height: 300px; vertical-align: top } ul { width: 1000%; position: absolute; list-style: none; left:0; top: 0; } .inner li{ float: left; } ol { position: absolute; height: 20px; right: 20px; bottom: 20px; text-align: center; padding: 5px; } ol li{ display: inline-block; width: 20px; height: 20px; line-height: 20px; background-color: #fff; margin: 5px; cursor: pointer; } ol .current{ background-color: red; } #arr{ display: none; } #arr span{ width: 40px; height: 40px; position: absolute; left: 5px; top: 50%; margin-top: -20px; background: #fff; cursor: pointer; line-height: 40px; text-align: center; font-weight: bold; font-family: '黑體'; font-size: 30px; color: #000; opacity: 0.5; border: 1px solid #fff; } #arr #right { right: 5px; left: auto; }第三部分是最主要的js代碼：
<script> /** * * @param id 傳入元素的id * @returns {HTMLElement | null} 返回標簽對象，方便獲取元素 */ function my$(id) { return document.getElementById(id); } //獲取各元素，方便操作 var box=my$("box"); var inner=box.children[0]; var ulObj=inner.children[0]; var list=ulObj.children; var olObj=inner.children[1]; var arr=my$("arr"); var imgWidth=inner.offsetWidth; var right=my$("right"); var pic=0; //根據li個數，創建小按鈕 for(var i=0;i<list.length;i++){ var liObj=document.createElement("li"); olObj.appendChild(liObj); liObj.innerText=(i+1); liObj.setAttribute("index",i); //為按鈕注冊mouseover事件 liObj.onmouseover=function () { //先清除所有按鈕的樣式 for (var j=0;j<olObj.children.length;j++){ olObj.children[j].removeAttribute("class"); } this.className="current"; pic=this.getAttribute("index"); animate(ulObj,-pic*imgWidth); } } //設置ol中第一個li有背景顏色 olObj.children[0].className = "current"; //克隆一個ul中第一個li,加入到ul中的最后=====克隆 ulObj.appendChild(ulObj.children[0].cloneNode(true)); var timeId=setInterval(onmouseclickHandle,1000); //左右焦點實現點擊切換圖片功能 box.onmouseover=function () { arr.style.display="block"; clearInterval(timeId); }; box.onmouseout=function () { arr.style.display="none"; timeId=setInterval(onmouseclickHandle,1000); }; right.onclick=onmouseclickHandle; function onmouseclickHandle() { //如果pic的值是5,恰巧是ul中li的個數-1的值,此時頁面顯示第六個圖片,而用戶會認為這是第一個圖, //所以,如果用戶再次點擊按鈕,用戶應該看到第二個圖片 if (pic == list.length - 1) { //如何從第6個圖,跳轉到第一個圖 pic = 0;//先設置pic=0 ulObj.style.left = 0 + "px";//把ul的位置還原成開始的默認位置 } pic++;//立刻設置pic加1,那么此時用戶就會看到第二個圖片了 animate(ulObj, -pic * imgWidth);//pic從0的值加1之后,pic的值是1,然后ul移動出去一個圖片 //如果pic==5說明,此時顯示第6個圖(內容是第一張圖片),第一個小按鈕有顏色, if (pic == list.length - 1) { //第五個按鈕顏色干掉 olObj.children[olObj.children.length - 1].className = ""; //第一個按鈕顏色設置上 olObj.children[0].className = "current"; } else { //干掉所有的小按鈕的背景顏色 for (var i = 0; i < olObj.children.length; i++) { olObj.children[i].removeAttribute("class"); } olObj.children[pic].className = "current"; } } left.onclick=function () { if (pic==0){ pic=list.length-1; ulObj.style.left=-pic*imgWidth+"px"; } pic--; animate(ulObj,-pic*imgWidth); for (var i = 0; i < olObj.children.length; i++) { olObj.children[i].removeAttribute("class"); } //當前的pic索引對應的按鈕設置顏色 olObj.children[pic].className = "current"; }; //設置任意的一個元素,移動到指定的目標位置 function animate(element, target) { clearInterval(element.timeId); //定時器的id值存儲到對象的一個屬性中 element.timeId = setInterval(function () { //獲取元素的當前的位置,數字類型 var current = element.offsetLeft; //每次移動的距離 var step = 10; step = current < target ? step : -step; //當前移動到位置 current += step; if (Math.abs(current - target) > Math.abs(step)) { element.style.left = current + "px"; } else { //清理定時器 clearInterval(element.timeId); //直接到達目標 element.style.left = target + "px"; } }, 10); }</script>所有用圖片如下：
1.jpg
2.jpg
3.jpg
4.jpg
5.jpg
下面是完整的代碼：
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>最簡單的輪播效果</title> <style> * { margin: 0; padding: 0 } .box { width: 500px; height: 300px; border: 1px solid #ccc; margin: 100px auto; padding: 5px; } .inner{ width: 500px; height: 300px; position: relative; overflow: hidden; } .inner img{ width: 500px; height: 300px; vertical-align: top } ul { width: 1000%; position: absolute; list-style: none; left:0; top: 0; } .inner li{ float: left; } ol { position: absolute; height: 20px; right: 20px; bottom: 20px; text-align: center; padding: 5px; } ol li{ display: inline-block; width: 20px; height: 20px; line-height: 20px; background-color: #fff; margin: 5px; cursor: pointer; } ol .current{ background-color: red; } #arr{ display: none; } #arr span{ width: 40px; height: 40px; position: absolute; left: 5px; top: 50%; margin-top: -20px; background: #fff; cursor: pointer; line-height: 40px; text-align: center; font-weight: bold; font-family: '黑體'; font-size: 30px; color: #000; opacity: 0.5; border: 1px solid #fff; } #arr #right { right: 5px; left: auto; } </style></head><body><div class="box" id="box"> <div class="inner"> <!--輪播圖--> <ul> <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/1.jpg" <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/2.jpg" <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/3.jpg" <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/4.jpg" <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="images/5.jpg" </ul> <ol class="bar"> </ol> <!--左右焦點--> <div id="arr"> <span id="left"> < </span> <span id="right"> > </span> </div> </div></div><script> /** * * @param id 傳入元素的id * @returns {HTMLElement | null} 返回標簽對象，方便獲取元素 */ function my$(id) { return document.getElementById(id); } //獲取各元素，方便操作 var box=my$("box"); var inner=box.children[0]; var ulObj=inner.children[0]; var list=ulObj.children; var olObj=inner.children[1]; var arr=my$("arr"); var imgWidth=inner.offsetWidth; var right=my$("right"); var pic=0; //根據li個數，創建小按鈕 for(var i=0;i<list.length;i++){ var liObj=document.createElement("li"); olObj.appendChild(liObj); liObj.innerText=(i+1); liObj.setAttribute("index",i); //為按鈕注冊mouseover事件 liObj.onmouseover=function () { //先清除所有按鈕的樣式 for (var j=0;j<olObj.children.length;j++){ olObj.children[j].removeAttribute("class"); } this.className="current"; pic=this.getAttribute("index"); animate(ulObj,-pic*imgWidth); } } //設置ol中第一個li有背景顏色 olObj.children[0].className = "current"; //克隆一個ul中第一個li,加入到ul中的最后=====克隆 ulObj.appendChild(ulObj.children[0].cloneNode(true)); var timeId=setInterval(onmouseclickHandle,1000); //左右焦點實現點擊切換圖片功能 box.onmouseover=function () { arr.style.display="block"; clearInterval(timeId); }; box.onmouseout=function () { arr.style.display="none"; timeId=setInterval(onmouseclickHandle,1000); }; right.onclick=onmouseclickHandle; function onmouseclickHandle() { //如果pic的值是5,恰巧是ul中li的個數-1的值,此時頁面顯示第六個圖片,而用戶會認為這是第一個圖, //所以,如果用戶再次點擊按鈕,用戶應該看到第二個圖片 if (pic == list.length - 1) { //如何從第6個圖,跳轉到第一個圖 pic = 0;//先設置pic=0 ulObj.style.left = 0 + "px";//把ul的位置還原成開始的默認位置 } pic++;//立刻設置pic加1,那么此時用戶就會看到第二個圖片了 animate(ulObj, -pic * imgWidth);//pic從0的值加1之后,pic的值是1,然后ul移動出去一個圖片 //如果pic==5說明,此時顯示第6個圖(內容是第一張圖片),第一個小按鈕有顏色, if (pic == list.length - 1) { //第五個按鈕顏色干掉 olObj.children[olObj.children.length - 1].className = ""; //第一個按鈕顏色設置上 olObj.children[0].className = "current"; } else { //干掉所有的小按鈕的背景顏色 for (var i = 0; i < olObj.children.length; i++) { olObj.children[i].removeAttribute("class"); } olObj.children[pic].className = "current"; } } left.onclick=function () { if (pic==0){ pic=list.length-1; ulObj.style.left=-pic*imgWidth+"px"; } pic--; animate(ulObj,-pic*imgWidth); for (var i = 0; i < olObj.children.length; i++) { olObj.children[i].removeAttribute("class"); } //當前的pic索引對應的按鈕設置顏色 olObj.children[pic].className = "current"; }; //設置任意的一個元素,移動到指定的目標位置 function animate(element, target) { clearInterval(element.timeId); //定時器的id值存儲到對象的一個屬性中 element.timeId = setInterval(function () { //獲取元素的當前的位置,數字類型 var current = element.offsetLeft; //每次移動的距離 var step = 10; step = current < target ? step : -step; //當前移動到位置 current += step; if (Math.abs(current - target) > Math.abs(step)) { element.style.left = current + "px"; } else { //清理定時器 clearInterval(element.timeId); //直接到達目標 element.style.left = target + "px"; } }, 10); }</script></body></html>希望本文所述對大家JavaScript程序設計有所幫助。
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