var tdate="06/23/2011 18:17:6";

function var_assign(){

var  day = document.alta.dia_nac.options[document.alta.dia_nac.selectedIndex].value;
		month = document.alta.mes_nac.options[document.alta.mes_nac.selectedIndex].value;
		year = document.alta.ano_nac.options[document.alta.ano_nac.selectedIndex].value;				
		seconddate = month + "/" + day + "/" + year + " 00:00:00";
}

function dateDiff(dateform) {
date1 = new Date();
date2 = new Date();
diff  = new Date();

date1temp = new Date(tdate);
date1.setTime(date1temp.getTime());

date2temp = new Date(seconddate);
date2.setTime(date2temp.getTime());

// sets difference date to difference of first date and second date

diff.setTime(Math.abs(date1.getTime() - date2.getTime()));

timediff = diff.getTime();

//weeks = Math.floor(timediff / (1000 * 60 * 60 * 24 * 7));
//timediff -= weeks * (1000 * 60 * 60 * 24 * 7);
days = Math.floor(timediff / (1000 * 60 * 60 * 24)) - 3 ; 
timediff -= days * (1000 * 60 * 60 * 24);
years = Math.floor(days / 365);

if (years < 13){ 
	top.location="http://www.terra.com/under13.html";
}
	
return false; // form should never submit, returns false
}