基于Java用户输入，设置Date（）对象的正确方法是什么

Question

I'm making an age verification modal and I'm a little stuck.

On lines 4-7 I create a javascript date object and try to fill it with the month, date and year, but it has become apparent to me that each of the lines 5-7 is overwritting the previous one.

$('#tier3').change(function(){
    var tier1 = $('#tier1').find(":selected").text();
     var tier2 = $('#tier2').find(":selected").text();
     var tier3 = $('#tier3').find(":selected").text();
     var userDOB = new Date();
     userDOB.setMonth(tier1);
     userDOB.setDate(tier2);
     userDOB.setFullYear(tier3);
     var now = Date.now();
     userAge = now - userDOB;
     if( userAge >= 588591547188){
        set_popup_cookie();
        popup_wrapper.style.visibility="hidden";
     }else {
        /*  window.location = "http://www.smokefree.gov/"; */
     }
});

I also tried substituting lines 4-7 with

var userDOB = Date.parse(tier . " " . tier2 . ", " . tier3 );

But I got a syntax error

Answer 1

you can use Date constructor new Date(year, month, day [, hour, minute, second, millisecond]);

as below

var userDOB = new Date(tier3, tier2, tier1);
var now = Date.now();
userAge = now - userDOB;
 if( userAge >= 588591547188){
    set_popup_cookie();
    popup_wrapper.style.visibility="hidden";
 }else {
    /*  window.location = "http://www.smokefree.gov/"; */
 }

check tier3, tier2, tier1 having expected values before calculating age