js原生带缩略图的图片切换效果

本例中用到的 moveElement(elementID,final_x,final_y,interval)是来自《JavaScript DOM编程艺术（中文第二版）》一书第10章中有一段代码。（可以直接baidu）

左边是banner图，右边是缩略图，当鼠标滑入缩略图时，也会切换图片。

一、这段是html代码，可以直接拷贝，需要自己准备相同大小的banner图，例中图片都是500x300

<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta http-equiv="X-UA-Compatible" content="ie=edge"><title>图片轮播</title><script src="./js.js"></script><style>* {margin: 0;padding: 0;word-break: break-all;}body {background: #FFF;color: #333;font: 12px/1.6em Helvetica, Arial, sans-serif;}a {color: #0287CA;text-decoration: none;}a:hover {text-decoration: underline;}ul,li {list-style: none;}fieldset,img {border: none;}legend {display: none;}em,strong,cite,th {font-style: normal;font-weight: normal;}input,textarea,select,button {font: 12px Helvetica, Arial, sans-serif;}table {border-collapse: collapse;}html {overflow: -moz-scrollbars-vertical;}#ifocus {width: 620px;height: 320px;margin: 20px;border: 1px solid #DEDEDE;background: #F8F8F8;}#ifocus_pic {display: inline;position: relative;float: left;width: 500px;height: 300px;overflow: hidden;margin: 10px 0 0 10px;}#ifocus_piclist {position: absolute;}#ifocus_piclist li {width: 500px;height: 300px;overflow: hidden;}#ifocus_piclist img {width: 500px;height: 300px;}#ifocus_btn {display: inline;float: right;width: 94px;margin: 9px 9px 0 0;}#ifocus_btn li {width: 94px;height: 57px;cursor: pointer;opacity: 0.5;-moz-opacity: 0.5;filter: alpha(opacity=50);}#ifocus_btn img {width: 80px;height: 50px;margin: 7px 0 0 11px;}#ifocus_btn .current {/* background: url(i/ifocus_btn_bg.gif) no-repeat; */opacity: 1;-moz-opacity: 1;filter: alpha(opacity=100);}</style>
</head><body><div id="ifocus"><div id="ifocus_pic"><div id="ifocus_piclist" style="left:0; top:0;"><ul><li><a href="#"><img src="./images/1.jpg" alt="" /></a></li><li><a href="#"><img src="./images/2.jpg" alt="" /></a></li><li><a href="#"><img src="./images/3.jpg" alt="" /></a></li><li><a href="#"><img src="./images/4.jpg" alt="" /></a></li><li><a href="#"><img src="./images/5.jpg" alt="" /></a></li></ul></div></div><div id="ifocus_btn"><ul><li class="current"><img src="./images/1.jpg" alt="" /></li><li><img src="./images/2.jpg" alt="" /></li><li><img src="./images/3.jpg" alt="" /></li><li><img src="./images/4.jpg" alt="" /></li><li><img src="./images/5.jpg" alt="" /></li></ul></div></div>
</body>
</html>

View Code

二、这段是js代码，其中用到了几个经典的js代码。在js中需要修改对应的id名字、图片移动的尺寸等。

function $(id) {return document.getElementById(id);
}function addLoadEvent(func) {var oldonload = window.onload;if (typeof window.onload != 'function') {window.onload = func;} else {window.onload = function () {oldonload();func();}}
}function moveElement(elementID, final_x, final_y, interval) {if (!document.getElementById) return false;if (!document.getElementById(elementID)) return false;var elem = document.getElementById(elementID);if (elem.movement) {clearTimeout(elem.movement);}if (!elem.style.left) {elem.style.left = "0px";}if (!elem.style.top) {elem.style.top = "0px";}var xpos = parseInt(elem.style.left);var ypos = parseInt(elem.style.top);if (xpos == final_x && ypos == final_y) {return true;}if (xpos < final_x) {var dist = Math.ceil((final_x - xpos) / 10);xpos = xpos   dist;}if (xpos > final_x) {var dist = Math.ceil((xpos - final_x) / 10);xpos = xpos - dist;}if (ypos < final_y) {var dist = Math.ceil((final_y - ypos) / 10);ypos = ypos   dist;}if (ypos > final_y) {var dist = Math.ceil((ypos - final_y) / 10);ypos = ypos - dist;}elem.style.left = xpos   "px";elem.style.top = ypos   "px";var repeat = "moveElement('"   elementID   "',"   final_x   ","   final_y   ","   interval   ")";elem.movement = setTimeout(repeat, interval);
}function classNormal(iFocusBtnID) {var iFocusBtns = $(iFocusBtnID).getElementsByTagName('li');for (var i = 0; i < iFocusBtns.length; i  ) {iFocusBtns[i].className = 'normal';}
}function classCurrent(iFocusBtnID, n) {var iFocusBtns = $(iFocusBtnID).getElementsByTagName('li');iFocusBtns[n].className = 'current';
}function iFocusChange() {if (!$('ifocus')) return false;$('ifocus').onmouseover = function () {atuokey = true};$('ifocus').onmouseout = function () {atuokey = false};var iFocusBtns = $('ifocus_btn').getElementsByTagName('li');var listLength = iFocusBtns.length;iFocusBtns[0].onmouseover = function () {moveElement('ifocus_piclist', 0, 0, 5);classNormal('ifocus_btn');classCurrent('ifocus_btn', 0);}if (listLength >= 2) {iFocusBtns[1].onmouseover = function () {moveElement('ifocus_piclist', 0, -300, 5);classNormal('ifocus_btn');classCurrent('ifocus_btn', 1);}}if (listLength >= 3) {iFocusBtns[2].onmouseover = function () {moveElement('ifocus_piclist', 0, -600, 5);classNormal('ifocus_btn');classCurrent('ifocus_btn', 2);}}if (listLength >= 4) {iFocusBtns[3].onmouseover = function () {moveElement('ifocus_piclist', 0, -900, 5);classNormal('ifocus_btn');classCurrent('ifocus_btn', 3);}}if (listLength >= 5) {iFocusBtns[4].onmouseover = function () {moveElement('ifocus_piclist', 0, -1200, 5);classNormal('ifocus_btn');classCurrent('ifocus_btn', 4);}}
}
setInterval('autoiFocus()', 3000);
var atuokey = false;function autoiFocus() {if (!$('ifocus')) return false;if (atuokey) return false;var focusBtnList = $('ifocus_btn').getElementsByTagName('li');var listLength = focusBtnList.length;for (var i = 0; i < listLength; i  ) {if (focusBtnList[i].className == 'current') var currentNum = i;}if (currentNum == 0 && listLength != 1) {moveElement('ifocus_piclist', 0, -300, 5);classNormal('ifocus_btn');classCurrent('ifocus_btn', 1);}if (currentNum == 1 && listLength != 2) {moveElement('ifocus_piclist', 0, -600, 5);classNormal('ifocus_btn');classCurrent('ifocus_btn',2);}if (currentNum == 2 && listLength != 3) {moveElement('ifocus_piclist', 0, -900, 5);classNormal('ifocus_btn');classCurrent('ifocus_btn',3);}if (currentNum == 3) {moveElement('ifocus_piclist', 0, -1200, 5);classNormal('ifocus_btn');classCurrent('ifocus_btn', 4);}if (currentNum == 4) {moveElement('ifocus_piclist', 0, 0, 5);classNormal('ifocus_btn');classCurrent('ifocus_btn',0);}}
addLoadEvent(iFocusChange);