find first and last day of month

day_of_month.php

<?php

function firstDayOfMonth() {
	return date("d", strtotime(date('m').'/01/'.date('Y').' 00:00:00'));
}

function lastDayOfMonth() {
	return date("d", strtotime('-1 second',strtotime('+1 month',strtotime(date('m').'/01/'.date('Y').' 00:00:00'))));
}

function getWeekofMonth( $startMonth, $endMonth ) {

	$startDay = 0;
	$endDay = 0;

	// find monday and friday of the current week starting from today
	switch ( $dayofWeek ) {
		case 1 :
			$startDay = $dayofMonth;
			$endDay = $dayofMonth + 5;
			break;
		case 2 :
			$startDay = $dayofMonth - 1;
			$endDay = $dayofMonth + 3;
			break;
		case 3:
			$startDay = $dayofMonth - 2;
			$endDay = $dayofMonth + 2;
			break;
		case 4:
			$startDay = $dayofMonth - 3;
			$endDay = $dayofMonth + 1;
			break;
		case 5:
			$startDay = $dayofMonth - 4;
			$endDay = $dayofMonth;
			break;
		case 6:
			$startDay = $dayofMonth + 2;
			$endDay = $dayofMonth + 6;
			break;
		case 7:
			$startDay = $dayofMonth + 3;
			$endDay = $dayofMonth + 7;
			break;
	}

	// if we are on the first / last day on the month..fix it
	if( $startDay < firstDayOfMonth() )
			$startDay = firstDayOfMonth();

	if( $endDay > lastDayOfMonth() )
			$endDay = lastDayOfMonth();


	// check if the first / last day of the month is not saturday / sunday
	$tmpStartDate = mktime(0,0,0, date("m"), $startDay, date("Y") );
	$tmpEndDate = mktime(0,0,0, date("m"), $endDay, date("Y") );

	// start saturday / sunday
	if( date("N", $tmpStartDate) == 6 )
			$startDay = $startDay - 1;
	if( date("N", $tmpStartDate) == 7 )
			$startDay = $startDay - 2;

	// end saturday / sunday
	if( date("N", $tmpEndDate) == 6 )
			$endDay = $endDay - 1;
	if( date("N", $tmpStartDate) == 7 )
			$endDay = $endDay - 2;


	// printing
	echo "monday : " .  date( "Y-m-d" , mktime(0,0,0, date("m"), $startDay, date("Y") ) ) . "\n";
	echo "friday : " . date( "Y-m-d" , mktime(0,0,0, date("m"), $endDay, date("Y") ) ) . "\n";
}



echo getWeekofMonth('2011-05-01 ', '2011-05-31');