//我现在下面li里的都是静态图片来的，现在想切换到哪个就显示拿个的大图，谁能帮下我，下面的写法好像不太对

//像这个网站右则上面的功能一样 http://www.smtsteel.com/
 <div class="boxminu_class" id="boxminu_class">
    <ul>
        <li class="a1"></li>
        <li class="a2"></li>
        <li class="a3"></li>
        <li class="a4"></li>
        <li class="a5"></li>
    </ul>
</div>
<div class="heightwhite">
</div>
<script type="text/javascript">
    var aLi = document.getElementById("boxminu_class").getElementsByTagName("li");
    var arr = [];
    for (var i = 0; i < aLi.length; i++) {
        arr[i] = (function (iNow) {
            aLi[i].onmouseover = function () {
                if (iNow == 0 ) {
                    this.className = 'a1_big';
                }
                if (iNow == 1) {
                    this.className ='a2_big';
                }
                if (iNow == 2) {
                    this.className = 'a3_big';
                }
                if (iNow == 3) {
                    this.className = 'a4_big';
                }
                if (iNow == 4) {
                    this.className = 'a4_big';
                }
            }
        })(i)
    }
</script>