i=0;
function nwin(url) {
if(i>0 && win1.closed==false){
	win1.close();
	}
var newwin;
win1 = window.open(url,newwin,"width=600,height=500,scrollbars=yes,resizable=yes");
i++;
}

i=0;
function nwin2(url,w,h) {
if(i>0 && win2.closed==false){
	win2.close();
	}
var newwin2;
win2 = window.open(url,newwin2,'width='+w+',height='+h+',scrollbars=yes,resizable=yes'); 
i++;
}