曜日を調べる

function bGETYOUBI($year,$mon,$day){
	#任意の日付けで曜日を出す
	$youbi=array('日','月','火','水','木','金','土');
	$y=$year; 
	$m=$mon; 
	$d=$day;
	if ($m < 3) {--$y; $m+=12;}
	$w=($y+ floor($y/4) - floor($y/100) + floor($y/400)+ floor((13*$m+8)/5) + $d) % 7;
	return "$youbi[$w]";#.$hol;
}