PHP Manual: Returns the day of the week

mixed jddayofweek ( int $julianday [, int $mode = CAL_DOW_DAYNO ] )

Returns the day of the week. Can return a string or an integer depending on the mode.

julianday

A julian day number as integer

mode

**Calendar week modes**
Mode	Meaning
0 (Default)	Return the day number as an int (0=Sunday, 1=Monday, etc)
1	Returns string containing the day of week (English-Gregorian)
2	Return a string containing the abbreviated day of week (English-Gregorian)

The gregorian weekday as either an integer or string.

JDDayOfWeek