Öffnen neuer Pages vermeiden

Hallo,
ich benutze das angehängte Script für meine Menüführung.

Wie kann man es verhindern, dass eine komplett neue Seite geöffnet wird, wenn man den link anwählt?

Vielen Dank, Grüße Dragon

JS
var height = 20; //
height of the menu headers
var iheight = 15; // height of the menu_items

var bgc = "lightyellow" // background color of the item
var tc = "black" // text color of the item

var over_bgc = "silver";
var over_tc = "red";

var speed = 0;
var timerID = "";
var N = (document.all) ? 0 : 1;
var width = 152

var self_menu = new Array();
function write_menu()
{
smc = 0; // count the position of the self_menu
document.write("<div style='position:absolute'>");
mn = 0;
mni = 1;
start = -1;

for(i=0;i<Link.length;i++)
{
la = Link[i].split("|");

if (la[0] == "0")
{
if(start == 0)
{
document.write("</div>");
h = csmc * iheight;
tmn = mn; //-h
self_menu[smc] = new Array(tmn,h,0,-2);
smc++;
mn--;
}
csmc = 0;
document.write("<div class='menu' style='top:"+mn+";height:"+height+"' id='down"+smc+"' onclick='pull_down("+smc+","+mni+")'>"+ la[1] + "</div>");
self_menu[smc] = new Array(mn,height,0,mni);
smc++;
mni++;
mn+=height;
start = 1;
}
else
{
if(start == 1)
{
if(N)mn+=2;
document.write("<div class='item_panel' id='down"+smc+"' style='top:"+mn+"'>");
start = 0;
}

document.write("<a href='"+la[2]+"'");
if (la[3] != "") document.write(" target='" + la[3] + "' ");
document.write("><div class='item' id='d"+i+"' style='height:"+iheight);
if (N) document.write(";width:150");
document.write("' onmouseover='color(this.id)' onmouseout='uncolor(this.id)'>"+ la[1] + "</div></a>");
csmc++;
}
}
if (start == 0)
{
document.write("</div>");
h = csmc * iheight;
tmn = mn + 5; //-h
self_menu[smc] = new Array(tmn,h,0);
name = "down" + (self_menu.length-1);
obj = document.getElementById(name);
obj.style.borderBottomColor = "darkblue";
obj.style.borderBottomWidth = 1;
obj.style.borderBottomStyle = "solid";
}
document.write("</div>");
}

function color(obj)
{
document.getElementById(obj).style.backgroundColor = over_bgc;
document.getElementById(obj).style.color = over_tc
}

function uncolor(obj)
{
document.getElementById(obj).style.backgroundColor = bgc;
document.getElementById(obj).style.color = tc
}

function pull_down(nr,c)
{
if (timerID == "")
{
to = self_menu[nr+1][1]
begin = nr + 2;
if (timerID != "") clearTimeout(timerID);
if (self_menu[nr+1][2] == 0)
{
self_menu[nr+1][2] = 1;
if(nr == self_menu.length-2) {to++;}
epull_down(begin,to,0);
}
else
{
to = 0;
self_menu[nr+1][2] = 0;
name = "down"+(nr+2);
open_item = 0;
for(i=0;i<nr;i++)
{
if(self_menu[i][2] == 1)
{open_item += self_menu[i][1];
}
}
if (N == false) {open_item-= (c*1)};
if (nr== self_menu.length-2) {val = self_menu[self_menu.length-1][1];to=-1;}
else val = parseInt(document.getElementById(name).style.top) -(open_item)-(c*height);
epull_up(begin,to,val);
}
}
}

function epull_down(nr,to,nowv)
{
name = "down" + (nr-1);
obj = document.getElementById(name).style.clip = "rect(0,"+width+","+(nowv+1)+",0)";
for (i=nr;i<self_menu.length;i++)
{
name = "down" + i;
obj = document.getElementById(name);
obj.style.top = parseInt(obj.style.top)+1;
}
nowv++;
if(nowv < to) timerID = setTimeout("epull_down("+nr+","+to+","+nowv+")",speed);
else timerID = "";
}

function epull_up(nr,to,nowv)
{
name = "down" + (nr-1);
obj = document.getElementById(name).style.clip = "rect(0,"+width+","+nowv+",0)";
for (i=nr;i<self_menu.length;i++)
{
name = "down" + i;
obj = document.getElementById(name);
obj.style.top = parseInt(obj.style.top)-1;
}
nowv--;
if(nowv > to) timerID = setTimeout("epull_up("+nr+","+to+","+nowv+")",speed);
else timerID = "";
}

function startup(nr)
{
write_menu();
if (nr != 0)
{
for(i=0;i<self_menu.length;i++)
{
if(self_menu[i][3] == nr) pull_down(i,nr)
i==self_menu.length;
}
}
}