Age verification problem

I am not very skillful with ActionScript, … although I managed to write a small script for age verification, for a alcoholic beverages site. The script gets two variables from two input text fields (19AB).

There are four frames[LIST=1]
[]input fields and continue button
[
]the verification script, that goes:

age = 0;
year = new Date();
yearBirth = 19+A+B;
yearCurrent = year.getFullYear();
age = yearCurrent-yearBirth ;

if (age >= 18) {
    gotoAndPlay(3);
}
else {
    gotoAndPlay(4);
}

[]video and continuation to the site
[
]“You can’t enter” message[/LIST]The problem is that it lets me through even if i don’t write anything in the input text fields :wasted:.

Any suggestions?