function chpage(url){
if (!win_closed(window.opener)){
	window.opener.focus();
	window.opener.location.href=url;
	}
else{
	window.open(url,"main","width=800,height=600,location=yes,menubar=yes,resizable=yes,scrollbars=yes,status=yes,toolbar=yes")
	}
}
function win_closed(winVar) {
	var ua = navigator.userAgent;
	if( !!winVar ){
		if( ( ua.indexOf('Gecko')!=-1 || ua.indexOf('MSIE 4')!=-1 || ua.indexOf('IE 5')!=-1 )
			&& ua.indexOf('Win')!=-1 ) {
			return winVar.closed; }
		else { return typeof winVar.document  != 'object';}
	}
	else {return true;}
}