js鼠标点击图片切换效果实现代码

<div id="menuWrapper" class="menuWrapper bg1">
 <ul class="menu" id="menu">
 <li class="bg1" style="background-position:0 0;">
 <a id="bg1" href="#">迈瑞宝</a>
 <ul class="sub1" style="background-position:0 0;">
 <li><a href="#">报价11.99-23.69万</a></li>
 <li><a href="#">车身结构三箱</a></li>
 <li><a href="#">油耗8.3-12.0L</a></li>
 </ul>
 </li>
 <li class="bg1" style="background-position:-266px 0px;">
 <a id="bg2" href="#">索纳塔8</a>
 <ul class="sub2" style="background-position:-266px 0;">
 <li><a href="#">报价13.39-22.59万</a></li>
 <li><a href="#">车身结构三箱</a></li>
 <li><a href="#">油耗9.0-12.0L</a></li>
 </ul>
 </li>
 <li class="last bg1" style="background-position:-532px 0px;">
 <a id="bg3" href="#">K5</a>
 <ul class="sub3" style="background-position:-266px 0;">
 <li><a href="#">报价10.88-25.58万</a></li>
 <li><a href="#">车身结构三箱</a></li>
 <li><a href="#">油耗8.4-13.0L</a></li>
 </ul>
 </li>
 </ul>
 </div>

ul.menu > li > a{
 float:left;
 width:265px;
 height:50px;
 margin-:450px;
 text-align:center;
 line-height:50px;
 color:#ddd;
 background-color:#333;
 letter-spacing:1px;
 cursor:pointer;
 text-decoration:none;
 text-shadow:0px 0px 1px #fff;
}
ul.menu > li ul{
 list-style:none;
 float:left;
 margin-:-180px;
 width:100%;
 height:110px;
 padding-:20px;
 background-repeat:no-repeat;
 background-color:transparent;
}
ul.menu > li ul li{
 display:none;
}
 ul.menu > li ul.sub1 {
 background-image: url('../img/bg1sub.png');
 }
 ul.menu > li ul.sub2 {
 background-image: url('../img/bg2sub.png');
 }
ul.menu > li ul.sub3{
 background-image:url(../img/bg3sub.png);
}
ul.menu > li ul li a{
 color:#fff;
 text-decoration:none;
 line-height:30px;
 margin-left:20px;
 text-shadow:1px 1px 1px #444;
 font-size:11px;
}
ul.menu > li ul li a:hover{
 border-bottom:1px dotted #fff;
}
ul.menu > li ul.sub1 li{
 display:block;
}

if (!document.defaultView || !document.defaultView.getComputedStyle) { // IE6-IE8
 var oldCurCSS = jQuery.curCSS;
 jQuery.curCSS = function (elem, name, force) {
  if (name === 'background-position') {
  name = 'backgroundPosition';
  }
  if (name !== 'backgroundPosition' || !elem.currentStyle || elem.currentStyle[name]) {
  return oldCurCSS.apply(this, arguments);
  }
  var style = elem.style;
  if (!force && style && style[name]) {
  return style[name];
  }
  return oldCurCSS(elem, 'backgroundPositionX', force) + ' ' + oldCurCSS(elem, 'backgroundPositionY', force);
 };
 }
 var oldAnim = $.fn.animate;
 $.fn.animate = function (prop) {
 if ('background-position' in prop) {
  prop.backgroundPosition = prop['background-position'];
  delete prop['background-position'];
 }
 if ('backgroundPosition' in prop) {
  prop.backgroundPosition = '(' + prop.backgroundPosition;
 }
 return oldAnim.apply(this, arguments);
 };
 function toArray(strg) {
 strg = strg.replace(/left|/g, '0px');
 strg = strg.replace(/right|bottom/g, '100%');
 strg = strg.replace(/([0-9\.]+)(\s|\)|$)/g, "$1px$2");
 var res = strg.match(/(-?[0-9\.]+)(px|\%|em|pt)\s(-?[0-9\.]+)(px|\%|em|pt)/);
 return [parseFloat(res[1], 10), res[2], parseFloat(res[3], 10), res[4]];
 }