从onchange事件处理程序中提取变量以用于其他功能

Question

I have an event handler listening for a change in a dropdown and setting the value of a variable. I have declared the variable as global ie outside of any functions, and then set the value on change. However, once it has changed I need to be able to pick up the variable in other functions (not within the even handler). How can i 'extract' it from within the event handler? I've tried to return it but no luck - here is the code:

$(document).on('change', 'select#search_subject', function () {
    if ($('#sBar3').show()) {
        $('#sBar3').hide();
    }
    var subject = $('#search_subject>option:selected').text();
    var id = $('#search_subject>option:selected').val();
    ajaxSubject(subject, '#sBar3');
    return subject;
});
console.log(subject);   

the log just shows 'empty string' and I'm baffled. If possible I dont want to rejig the code to include everything within the event handler (there's lots of Google Map generating code in there and it will make for a pain) - i just need to get the subject variable out of the event handler if that makes sense - Thanks

Answer 1

By using the var keyword, you're creating a new local variable, which you're then assigning the subject text to. If you've already defined subject in the global scope, then your assignment line should simply be:

subject = $('#search_subject>option:selected').text();

Answer 2

If the select is not created later, then this would be simpler code after you remove the var that makes subject local

$("#search_subject").on('change',function () {
  $('#sBar3').toggle();
  subject = $('option:selected',this).text();
  var id = $(this).val(); // not used?
  ajaxSubject(subject, '#sBar3');
  window.console && console.log(subject);   
  return subject;
});