无法使我的验证功能正常工作

Question

I have these two functions to calculate the persons age after they enter a date in the form MM/DD/YYYY. When it gets to the part if(age<21) and the age is under, it will alert the user with my message but will not return false. I just cant figure it out been working on it forever. Thanks for any help!

function validateAge()
{
    var x = /^\s*/;
    var datemsg = "";

    var inputDate = document.code.myDate.value;
    inputDate = inputDate.replace(x, "");
    document.code.myDate.value = inputDate;

    getAge(new Date(inputDate));

    return true;

}

function getAge(birth)
{

    var today = new Date();
    var nowyear = today.getFullYear();
    var nowmonth = today.getMonth();
    var nowday = today.getDate();

    var birthyear = birth.getFullYear();
    var birthmonth = birth.getMonth();
    var birthday = birth.getDate();

    var age = nowyear - birthyear;
    var age_month = nowmonth - birthmonth;
    var age_day = nowday - birthday;

    if(age_month < 0 || (age_month == 0 && age_day <0)) 
    {
            age = parseInt(age) -1;
     }
    //alert(age);

    if(age < 21)
    {
    alert("You are not of drinking age");
    return false;
    }


}

Answer 1

If you're correctly seeing the alert when you should then in the validateAge function change

getAge(new Date(inputDate));

return true;

to

return getAge(new Date(inputDate));

You'll also need to add

return true;

to the end of your getAge() function so that it always returns a value.

Answer 2

You are not returning the result of getAge in the validateAge function ie validateAge always returns true. You need to do something in validateAge with the return value of getAge eg

function validateAge()
{
    var x = /^\s*/;
    var datemsg = "";

    var inputDate = document.code.myDate.value;
    inputDate = inputDate.replace(x, "");
    document.code.myDate.value = inputDate;    

    return getAge(new Date(inputDate));    
}

function getAge(birth)
{
    var today = new Date();
    var nowyear = today.getFullYear();
    var nowmonth = today.getMonth();
    var nowday = today.getDate();

    var birthyear = birth.getFullYear();
    var birthmonth = birth.getMonth();
    var birthday = birth.getDate();

    var age = nowyear - birthyear;
    var age_month = nowmonth - birthmonth;
    var age_day = nowday - birthday;

    if(age_month < 0 || (age_month == 0 && age_day <0)) 
    {
        age = parseInt(age) -1;
    }
    //alert(age);

    if(age < 21)
    {
        alert("You are not of drinking age");
        return false;
    }
    else
    {
        return true;
    }
}

Answer 3

In your function validateage, you are calling the function getAge, but not doing anything based on the value it returns. You are assuming, I believe, that the validateage function should end if getAge returns false. Rather the function is simply executing and then just ignores the return value, then goes to the next line and returns true. Try:

if (!getAge(new Date(inputDate))) {
return false;
} else {
return true;
}