shown=''
function popup(url){
	if( shown=='' || shown.closed) {
		shown=window.open(url,'OpenFile','scrollbars=no,status=no,high,width=500,height=400');
	}else{
		shown.close();
		shown=window.open(url,'OpenFile','scrollbars=no,status=no,high,width=500,height=400');
	}
}