public static function firstDayOfMonth($ts = null)
	{
		// default to now
		if ($ts === null) $ts = sfDateTimeToolkit::now();
		
		return sfTime::subtractDay($ts, date('d', $ts) - 1);
	}
public static function firstDayOfMonth($ts = null)
	{
		// default to now
		if ($ts === null) $ts = sfDateTimeToolkit::now();
		
		return sfTime::subtractDay($ts, date('d', $ts) - 1);
	}
public static function firstDayOfMonth ( $ ts = null ) { // default to now if ( $ ts === null ) $ ts = sfDateTimeToolkit :: now ( ) ; return sfTime :: subtractDay ( $ ts , date ( 'd' , $ ts ) - 1 ) ; }
Returns the timestamp for first day of the month for the given date.

@param	timestamp
@return	timestamp
Returns the timestamp for first day of the month for the given date .