I need my javascript to only do the callback when I OPEN a section on the accordion, as of right now it does a callback when I open OR close a section because I'm only using a click function. Is there a way I can modify my existing click function to only run when the given section is activated?

My current click function:

$("a#mimetypes").click(function() {
    $("span#mimetypesthrobber").loading(true, { max: 1500 })
    $.getJSON("../mimetypes", function(data) {
        //callback
    });
});

Thanks!

EDIT:

I already tried this with another part of the accordion and it wasn't working properly:

$('.ui-accordion').bind('accordionchange', function(event, ui) {
if (ui.newHeader == "Encoders") {
EncodersGet();
}
});