Why does iphone skip age verification?

Question

iPhone

Hello!
I can't understand why iphone doesn't take into account the condition, but android does.
I have the following check for age

var bDay = ""+yearVal+"-"+monthVal+"-"+dayVal+"";
var checkAge = Math.floor((new Date().getTime() - new Date(bDay)) / (24 * 3600 * 365.25 * 1000));
if(checkAge < 18) {
    $(".error").show();
        return;
}

The problem is only on iPhones, it skips this check and moves on, what could be causing it?

Answer 1

a) In order to avoid misunderstandings with the date format of the input string, substitute the parameters explicitly: b) It is also useful to reduce the time to one value for comparison:
PS: In general, the age must be calculated for each component of the date, so as not to run into leap years:

var now = new Date();
var age = (now.getFullYear() - yearVal - ((now.getMonth() - (monthVal - 1) || now.getDate() - dayVal) < 0 ? 1 : 0));