{literal}
<script type="text/javascript">

var startyear = "1950";
var endyear = "2010";
var dat = new Date();
var curday = dat.getDate();
var curmon = dat.getMonth()+1;
var curyear = dat.getFullYear();

function checkleapyear(datea)

{

    if(datea.getYear()%4 == 0)

    {

        if(datea.getYear()% 10 != 0)

        {

            return true;

        }

        else

        {

            if(datea.getYear()% 400 == 0)

                return true;

            else

                return false;

        }

    }

return false;

}

function DaysInMonth(Y, M) {

    with (new Date(Y, M, 1, 12)) {

        setDate(0);

        return getDate();

    }

}

function datediff(date1, date2) {

    var y1 = date1.getFullYear(), m1 = date1.getMonth(), d1 = date1.getDate(),

     y2 = date2.getFullYear(), m2 = date2.getMonth(), d2 = date2.getDate();



    if (d1 < d2) {

        m1--;

        d1 += DaysInMonth(y2, m2);

    }

    if (m1 < m2) {

        y1--;

        m1 += 12;

    }

    return [y1 - y2, m1 - m2, d1 - d2];

}

function calage()

{

var calday = document.birthday.day.options[document.birthday.day.selectedIndex].value;

var calmon = document.birthday.month.options[document.birthday.month.selectedIndex].value;

var calyear = document.birthday.year.options[document.birthday.year.selectedIndex].value;

        var curd = new Date(curyear,curmon-1,curday);

        var cald = new Date(calyear,calmon-1,calday);

        var diff =  Date.UTC(curyear,curmon,curday,0,0,0) - Date.UTC(calyear,calmon,calday,0,0,0);

        var dife = datediff(curd,cald);

        document.birthday.age.value=dife[0]+" years, "+dife[1]+" months, and "+dife[2]+" days";

    }

}

</script>
{/literal}


<form name="birthday">
Date<select name="day" size="1">
<script type="text/javascript">
document.write("<option value={$extra_fields.0.field_value}>{$extra_fields.0.field_value}</option>");
</script></select> 
Month<select name="month" size="1">
<script type="text/javascript">
document.write("<option value={$extra_fields.1.field_value}>{$extra_fields.1.field_value}</option>");
</script></select> 
Year<select name="year" size="1">
<script type="text/javascript">
document.write("<option value={$extra_fields.2.field_value}>{$extra_fields.2.field_value}</option>");
</script></select>
<input name="start" onclick="calage()" value="Calculate" type="button"><br>
<input name="age" size="40" value="Result"><br>
</tr> </table> </form>