Change your onclick event to:onClick="call_server('01');"
Change your callserver() function to:var z;
function call_server(page){
z=escape(page);
var x=document.getElementById("selector");
request.open("GET","PluginPage"+z+".asp");
request.onreadystatechange=sever_interaction;
request.send("url="+x.options[x.selectedIndex].value);
}
Change your sever_interaction() function to:function sever_interaction(){
if(request.readyState==1)document.getElementById("div"+z).innerHTML="loading...";
else if(request.readyState==4)document.getElementById("div"+z).innerHTML=request.responseText;
}
Finally, give all your divisions ids such as div01, div02, etc.