关于JSP中链接跳转的问题

我用javascript写了一个图片动态转换的效果，然后点击图片会跳入相应链接，如下javascript代码是我从其他项目代码移植过来的，结果我发现当点击进入链接页面的时候会从新打开一个新的页面，可是我想把初始的页面转换成新的页面，谁懂下列代码并且知道如何设置的，求指教！
var isIE = (document.all) ? true : false;
var $ = function (id) {
return "string" == typeof id ? document.getElementById(id) : id;
};
var Class = {
create: function() {
return function() { this.initialize.apply(this, arguments); }
}
}
var Extend = function(destination, source) {
for (var property in source) {
destination[property] = source[property];
}
}
var Bind = function(object, fun) {
return function() {
return fun.apply(object, arguments);
}
}
var Each = function(list, fun){
for (var i = 0, len = list.length; i < len; i++) { fun(list[i], i); }
};
//ie only
var RevealTrans = Class.create();
RevealTrans.prototype = {
initialize: function(container, options) {
this._img = document.createElement("img");
this._a = document.createElement("a");
this._timer = null;//计时器
this.Index = 0;//显示索引
this._onIndex = -1;//当前索引

this.SetOptions(options);

this.Auto = !!this.options.Auto;
this.Pause = Math.abs(this.options.Pause);
this.Duration = Math.abs(this.options.Duration);
this.Transition = parseInt(this.options.Transition);
this.List = this.options.List;
this.onShow = this.options.onShow;

//初始化显示区域
this._img.style.visibility = "hidden";//第一次变换时不显示红x图
this._img.style.width = this._img.style.height = "100%"; this._img.style.border = 0;
this._img.onmouseover = Bind(this, this.Stop);
this._img.onmouseout = Bind(this, this.Start);
isIE && (this._img.style.filter = "revealTrans()");

this._a.target = "_blank";

$(container).appendChild(this._a).appendChild(this._img);
},
//设置默认属性
SetOptions: function(options) {
this.options = {//默认值
Auto: true,//是否自动切换
Pause: 1000,//停顿时间(微妙)
Duration: 1,//变换持续时间(秒)
Transition: 7,//变换效果(23为随机)
List: [],//数据集合,如果这里不设置可以用Add方法添加
onShow: function(){}//变换时执行
};
Extend(this.options, options || {});
},
Start: function() {
clearTimeout(this._timer);
//如果没有数据就返回
if(!this.List.length) return;
//修正Index
if(this.Index < 0 || this.Index >= this.List.length){ this.Index = 0; }
//如果当前索引不是显示索引就设置显示
if(this._onIndex != this.Index){ this._onIndex = this.Index; this.Show(this.List[this.Index]); }
//如果要自动切换
if(this.Auto){
this._timer = setTimeout(Bind(this, function(){ this.Index++; this.Start(); }), this.Duration * 1000 + this.Pause);
}
},
//显示
Show: function(list) {
if(isIE){
//设置变换参数
with(this._img.filters.revealTrans){
Transition = this.Transition; Duration = this.Duration; apply(); play();
}
}
this._img.style.visibility = "";
//设置图片属性
this._img.src = list.img; this._img.alt = list.text;
//设置链接
!!list["url"] ? (this._a.href = list["url"]) : this._a.removeAttribute("href");
//附加函数
this.onShow();
},
//添加变换对象
Add: function(sIimg, sText, sUrl) {
this.List.push({ img: sIimg, text: sText, url: sUrl });
},
//停止
Stop: function() {
clearTimeout(this._timer);
}
};