function getTotalDaysOfMonth() {
		var actualDate = new Date();
		var month = actualDate.getMonth();
		if (month == 0 || month == 2 || month == 4 || month == 6 || month == 7 || month == 9 || month == 11) {
			return 31;
		} else if (month == 3 || month == 5 || month == 8 || month == 10) {
			return 30;
		} else if (month == 2) {
			if (actualYearIsLeap()) {
				return 29;
			} else {
				return 28;
			}
		} else {
			return 0;
		}
	}
function actualYearIsLeap() {
		var actualDate = new Date();
		var year = actualDate.getYear();
        if ((year % 4 == 0 && year % 100 != 0) 
			|| year % 400 == 0) {
            return true;
        } else {
            return false;
		}
	}   
function readCookie(name) {
		var nameEQ = name + "=";
		var ca = document.cookie.split(';');
		for (var i = 0; i < ca.length; i++) {
			var c = ca[i];
			while (c.charAt(0) == ' ') {
				c = c.substring(1, c.length);
			}
			if (c.indexOf(nameEQ) == 0) {
				return c.substring(nameEQ.length, c.length);
			}
		}
		return null;
	}
function createCookie(name, value, days) {
		if (days) {
			var date = new Date();
			date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
			var expires = "; expires=" + date.toGMTString();
		}
		else {
			var expires = "";
		}
		document.cookie = name + "=" + value + expires + "; path=/";
	}

var date = new Date();
var mes = date.getMonth() + 1;
var anio = (date.getYear() < 1000) ? date.getYear() + 1900 : date.getYear();
var nombreCookie = 'sl_' + mes + "_" + anio;
var cookie = readCookie(nombreCookie);
if (cookie == null) {
	// grabar una sola vez por usuario
	cookie = "0";
	var daysLeft = getTotalDaysOfMonth() - date.getDate() + 1;
	createCookie(nombreCookie, cookie, daysLeft);
	var imagen = new Image();
	imagen.src = 'http://www.antel.com.uy/resolucion/index.aspx?width=' + screen.width + '&height=' + screen.height;
}