function go( url, opt, tb, w, h, s, r ){
	
	if( !url )return false;
	
	l = ( screen.width - w )/2;
	t = ( screen.height - h )/2;
	if( !w )w = 700;
	if( !h )h = 500;
	if( !s )s = 1; else s = 0;
	if( !r )r = 1; else r = 0;
	if( !tb )tb = 1; else tb = 0;
	
	if( opt == 1 ){
		window.open( url, "_blank", "toolbar="+tb+",scrollbars="+s+",resizable="+r+",left="+l+",top="+t+",width="+w+",height="+h );
	}
	else if( opt == 2 ){
		window.open( url, "_blank" );
	}
	else{
		window.location.href = url;
	}
}