function calendarURL()
{

var starting_year = 2010;
var ending_year = 2011;
var d = new Date();
var month = d.getMonth() + 1;
var year =  d.getFullYear();

	function makeCalendarURL(mode)
	{
		var calURL;
		
		if (mode > 0)
		{
			if (month == 12)
			{
				month = 1;
				year = ending_year;
			}
			else
			{
				month++;
			}
		}
		else if (mode < 0)
		{
			if (month == 1)
			{
				month = 12;
				year = starting_year;
			}
			else
			{
				month--;
			}
		}
		
		if (year > ending_year)
			year = ending_year;
		
		if (year >= ending_year && month > 6)
		{
			month = 6;
			year = ending_year;
		}
		
		if (year < starting_year)
			year = starting_year;
			
		if (year <= starting_year && month < 8)
		{
			month = 8;
			year = starting_year;
		}
		
		calURL = "calendar/Month_" + month + "_1_" + year + "_0.jpg";
		
		return (calURL);
	}

	this.setCalendarURL = function(mode)
	{
		var calURL = makeCalendarURL(mode);
		
		document.getElementById('calendar').src = calURL;
	}

}