How to chang date 1940 to 2030

I am use Birthday Selection filed

Use this js.

if (parseInt($('select.bxcft-birthdate-year').children(':last').val()) !== 1940) {
            $('select.bxcft-birthdate-year').children('option:not(:first)').remove();
            for ( var i = 2030; i >= 1940; i-=1 ) {
                $("<option></option>").attr('value', i).text(i).appendTo('select.bxcft-birthdate-year');
            }
        }

Should modify the current values of your birthdate field with 2030 and 1940.

I want to change this admin side when I add birthday selection field in registration form

ok thank you its work.

@adnanlimdi
@atallos

how can i add this js to my theme?
function.php? or?