function windowopen(url){
   var str="toolbar=no,location=no,status=no,menubar=no,scrollbars=no";
   if(screen.height<=768 ){
       var wl=0;
	   var wt=0;
       var ww=screen.availWidth;
       var wh=screen.availHeight;
       str+=",left=0";
	   str+=",top=0";
       str+=",width="+ww;
	   str+=",height="+wh; 
	}else{
	   wl=(screen.width-1024)/2;
	   wt=(screen.height-768)/2;
       ww=1024;
	   wh=768;
	   str+=",left="+wl;
	   str+=",top="+wt;
       str+=",width="+ww; 
	   str+=",height="+wh;
   }

   var tmp=window.open(url,'imiu',str);
   tmp.focus();
   tmp.moveTo(wl,wt);
   tmp.resizeTo(ww,wh);
}