public getDay() : Number
Returns the day of the week (0 for Sunday, 1 for Monday, and so on) of the specified Date object according to local time. Local time is determined by the operating system on which Flash Player is running.
Number - An integer representing the day of the week.
The following example creates a new Date object and uses getDay() to determine the current day of the week:
var dayOfWeek_array:Array = new Array("Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday");
var today_date:Date = new Date();
var day_str:String = dayOfWeek_array[today_date.getDay()];
trace("Today is "+day_str);