I\'ve made a jquery/ajax function that updates #courses, sending #fos\'s .val() and .text(), specifically of the one that is selected, like so:
$(\'#selling #fos
You can also use jQuery's second argument (context) to avoid the unnecessary "filter", "find", "children" etc. This allows your selector to be something like:
$('select[name="myselect"]').on('change',function(){
var selectedOptionName = $('option:selected',this).text();
console.log(selectedOptionName);
});