$.throttle = jq_throttle = function( delay, no_trailing, callback, debounce_mode ) {
    // After wrapper has stopped being called, this timeout ensures that
    // `callback` is executed at the proper times in `throttle` and `end`
    // debounce modes.
    var timeout_id,
      
      // Keep track of the last time `callback` was executed.
      last_exec = 0;
    
    // `no_trailing` defaults to falsy.
    if ( typeof no_trailing !== 'boolean' ) {
      debounce_mode = callback;
      callback = no_trailing;
      no_trailing = undefined;
    }
    
    // The `wrapper` function encapsulates all of the throttling / debouncing
    // functionality and when executed will limit the rate at which `callback`
    // is executed.
    function wrapper() {
      var that = this,
        elapsed = +new Date() - last_exec,
        args = arguments;
      
      // Execute `callback` and update the `last_exec` timestamp.
      function exec() {
        last_exec = +new Date();
        callback.apply( that, args );
      };
      
      // If `debounce_mode` is true (at_begin) this is used to clear the flag
      // to allow future `callback` executions.
      function clear() {
        timeout_id = undefined;
      };
      
      if ( debounce_mode && !timeout_id ) {
        // Since `wrapper` is being called for the first time and
        // `debounce_mode` is true (at_begin), execute `callback`.
        exec();
      }
      
      // Clear any existing timeout.
      timeout_id && clearTimeout( timeout_id );
      
      if ( debounce_mode === undefined && elapsed > delay ) {
        // In throttle mode, if `delay` time has been exceeded, execute
        // `callback`.
        exec();
        
      } else if ( no_trailing !== true ) {
        // In trailing throttle mode, since `delay` time has not been
        // exceeded, schedule `callback` to execute `delay` ms after most
        // recent execution.
        // 
        // If `debounce_mode` is true (at_begin), schedule `clear` to execute
        // after `delay` ms.
        // 
        // If `debounce_mode` is false (at end), schedule `callback` to
        // execute after `delay` ms.
        timeout_id = setTimeout( debounce_mode ? clear : exec, debounce_mode === undefined ? delay - elapsed : delay );
      }
    };
    
    // Set the guid of `wrapper` function to the same of original callback, so
    // it can be removed in jQuery 1.4+ .unbind or .die by using the original
    // callback as a reference.
    if ( $.guid ) {
      wrapper.guid = callback.guid = callback.guid || $.guid++;
    }
    
    // Return the wrapper function.
    return wrapper;
};

$(function() {
    var apiKey = 'YFYBcss2cyyPXkIDhYda0Oiu458ZoV2Ox88OS0jC5A55Yb2jJTAyR90pNIUXv3Uy';

    var wrappers = $('.slider-wrapper');
    function scan() {
        var scrollTop = $(window).scrollTop(),
            height = $(window).height(),
            left = [];

        wrappers.each(function() {
            var wrapper = $(this);
            var threadUrls = [];
            var elemsByThreadUrl = {};
                
            if (wrapper.position().top > scrollTop + height) {
                left.push(wrapper);
                return;
            }

            wrapper.find('[data-disqus-thread-url]').each(function() {
                var url = $(this).attr('data-disqus-thread-url');
                threadUrls.push('link:' + url);
                elemsByThreadUrl[url] = this;
            });

            $.ajax({
                url: 'http://disqus.com/api/3.0/threads/list.jsonp',
                data: {
                    forum: 'chicagoist',
                    thread: threadUrls,
                    api_key: apiKey,
                    limit: 100
                },
                type: 'GET',
                dataType: 'jsonp',
                success: function(data) {
                    $.each(data.response, function(_, thread) {
                        var elem = elemsByThreadUrl[thread.link];
                        if (!elem)
                            return;
                        elem.innerHTML = thread.posts;
                    });
                }
            });
        });
        wrappers = $(left);
    }

    scan();
    $(document).scroll($.throttle(333, scan));
});