var now = new Date();
var yearNow = now.getFullYear();
var monthNow = now.getMonth();
var monthNow = monthNow + 1;
var dateNow = now.getDate();
var dob = new Date("December 20, 1996");
var yearDob = dob.getFullYear();
var monthDob = dob.getMonth();
var monthDob = monthDob + 1;
var dateDob = dob.getDate();
var pluralY = ("s");
var pluralM = ("es");
var pluralD = ("s");
var yearAge = yearNow - yearDob;
if (monthNow >= monthDob)
var monthAge = monthNow - monthDob;
else {
yearAge--;
var monthAge = 12 + monthNow - monthDob;
}
if (dateNow >= dateDob)
var dateAge = dateNow - dateDob;
else {
monthAge--;
var dateAge = 31 + dateNow - dateDob;
if (monthAge < 0) {
monthAge = 11;
yearAge--; 
}
} 
if (yearAge == 0)
	printYear = ("");
else
	printYear = (yearAge + " a&ntilde;o" + pluralY + ", ");
if (yearAge == 1)
	pluralY = ("");
if (monthAge == 1)
	pluralM = ("");
if (dateAge == 1)
	pluralD = ("");
if (dateAge == 0)
	printDay = ("&nbsp;hoy");
else
	printDay = ("&nbsp;y " + dateAge + "&nbsp;d&iacute;a" + pluralD + "&nbsp;de antig&uuml;edad");
printMonth = (monthAge + "&nbsp;mes" + pluralM); 
printText = (printYear + printMonth + printDay);
if (monthAge == 0 && dateAge == 0)
	printText = ("<B>" + yearAge + " a&ntilde;o" + pluralY + " de antig&uuml;edad hoy");
document.write("Esta website tiene " + printText);