function addEvent(element, type, handler) {
  // assign each event handler a unique ID
  if (!handler.$$guid) handler.$$guid = addEvent.guid++;
  // create a hash table of event types for the element
  if (!element.events) element.events = {};
  // create a hash table of event handlers for each element/event pair
  var handlers = element.events[type];
  if (!handlers) {
    handlers = element.events[type] = {};
    // store the existing event handler (if there is one)
    if (element["on" + type]) {
      handlers[0] = element["on" + type];
    }
  }
  // store the event handler in the hash table
  handlers[handler.$$guid] = handler;
  // assign a global event handler to do all the work
  element["on" + type] = handleEvent;
};
// a counter used to create unique IDs
addEvent.guid = 1;

function removeEvent(element, type, handler) {
  // delete the event handler from the hash table
  if (element.events && element.events[type]) {
    delete element.events[type][handler.$$guid];
  }
};

function handleEvent(event) {
  // grab the event object (IE uses a global event object)
  event = event || window.event;
  // get a reference to the hash table of event handlers
  var handlers = this.events[event.type];
  // execute each event handler
  for (var i in handlers) {
    this.$$handleEvent = handlers[i];
    this.$$handleEvent(event);
  }
};

// preserve old onload eventss
addHandlersLoadEvent = function(f) { var old = window.onload
	if (typeof old != 'function') window.onload = f
	else { window.onload = function() { old(); f() }}
}

function handleClick(old, href) {
    return function() {
        old();
        pageTracker._trackPageview('/preview/'+href); 
    }
}

function registerHandlers() {
    var all = document.getElementsByTagName('a');
    for (var i = 0, o; o = all[i]; i++) {
			if(o.href.match(/\.mp3$/i)) {
                var old = o.previousSibling.onclick;
                var href = o.getAttribute("href", 2);
                o.previousSibling.onclick = handleClick(old, href);
            }
	}

}

addHandlersLoadEvent(registerHandlers);