function changeCoord(id, left) {
$$(id).style.left = left;
}
function $$(id) {
return document.getElementById(id);
}
function $$$(id) {
return document.getElementsByClassName(id)[0];
}
function indexOf(arry, obj) {
for (var i = 0; i < arry.length; i++) {
if (obj == arry[i]) {
return i;
}
};
}
window.onload = function() {
//給頁面上所有的滑塊注冊事件
//products-box-center 父容器對象

var obj = document.getElementsByClassName('products-box-center');
for(var i=0;i<obj.length;i++){
try{
var base=obj[i].getElementsByClassName('products-box-center-title')[0]; //取得每一項標題
var elems=base.getElementsByClassName('products-items-title');
for(var j=0;j<elems.length;j++){
var elem=elems[j];
elem.onmousemove=function(){
//獲得當前對象的父容器的父容器
var baseElem=this.parentElement.parentElement;
var baseIndex=indexOf(obj,baseElem)+1;

//獲得當前對象的坐標
var left = this.offsetLeft;

//獲得對應的滑塊對象
var slider=$$('products-triangle-'+baseIndex);

//改變滑塊的坐標
slider.style.left = left + "px";
//改變當前對象和其他對象的顏色
this.style.color = "red";
//獲取當前父容器下面的所有元素
var notes=this.parentElement.getElementsByClassName('products-items-title');
for(var k=0;k<notes.length;k++){
if(this!=notes[k])
notes[k].style.color="#666";
}

};
}

}
catch(e){
alert(e);
}
};
}

<div class="products-box-center">
<div class="products-box-center-title">
<div class="products-items-title products-focus-text"><h3>最新商品</h3></div>
<div class="products-items-title"><h3>筆記本</h3></div>
<div class="products-items-title"><h3>數碼影音</h3></div>
<div class="products-items-title"><h3>配件</h3></div>
<div class="products-items-title"><h3>辦公打印</h3></div>
<div class="products-bottom-triangle" id="products-triangle-${index.count}"><b class="triangle"></b></div>
</div>

<div class="products-box-panel">

<div class="products-item">

<ul>
<c:forEach begin="1" end="10">
<li>
<a href="#"><img src="img/pc.jpg"/></a>
<div class="p-name">
<a href="#">LG IPS237L-BN 23英寸IPS顯示器</a>
</div>

<div class="p-price">
<span>￥1299.00</span>
</div>

</li>
</c:forEach>
</ul>
</div>

</div>

</div>