<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title></title> <style type="text/css"> * { margin: 0; padding: 0; } #outer { width: 500px; margin: 50px auto; padding: 10px; background-color: greenyellow; /*設置文本居中*/ text-align: center; } </style> <script type="text/javascript"> window.onload = function() { //獲取兩個按鈕 var prev = document.getElementById("prev"); var next = document.getElementById("next"); //獲取img標籤(獲取到的是一個數組,取第一個索引爲0) var img = document.getElementsByTagName("img")[0]; //建立一個數組,用來保存圖片的路徑 var imgArr = ["../../img/111.jpg", "../../img/222.jpg", "../../img/333.jpg", "../../img/444.jpg"]; var index = 0; //顯示當前張數 var info = document.getElementById("info"); info.innerHTML = "一共" + imgArr.length + "張圖片" + "當前張數爲第" + (index + 1) + "張"; prev.onclick = function() { index--; if(index < 0) { index = imgArr.length - 1; } img.src = imgArr[index]; //從新加載當前張數 info.innerHTML = "一共" + imgArr.length + "張圖片" + "當前張數爲第" + (index + 1) + "張"; } next.onclick = function() { index++; if(index > imgArr.length - 1) { index = 0; } img.src = imgArr[index]; //從新加載當前張數 info.innerHTML = "一共" + imgArr.length + "張圖片" + "當前張數爲第" + (index + 1) + "張"; } } </script> </head> <body> <div id="outer"> <p id="info"></p> <--默認顯示圖片--> <img src="../../img/222.jpg" /> <button id="prev">上一張</button> <button id="next">下一張</button> </div> </body> </html>