gistfile1.js

$(document).click(function(event) { 
    if ($('.popup-content').is(":visible")) {
        $('.popup-content').fadeOut('slow', function() {})   
    }
});

$('#popup').click(function(event) { 
    if ($('.popup-content').is(":visible")) {       
        $('.popup-content').fadeOut('slow', function() {})   
    } else {
        $('.popup-content').fadeIn('slow', function() {})    
    }

    event.stopPropagation();
});

$('.popup-content').click(function(event) {
    event.stopPropagation();
});