Warum funktioniert das „onclick'-Ereignis meines JS-„li'-Tags in IE8 nicht und wie kann ich es beheben?

var hookEvent = (function() {
    var div;

    function standardHookEvent(element, eventName, handler) {
        element.addEventListener(eventName, handler, false);
        return element;
    }

    function oldIEHookEvent(element, eventName, handler) {
        element.attachEvent("on" + eventName, function(e) {
            e = e || window.event;
            e.preventDefault = oldIEPreventDefault;
            e.stopPropagation = oldIEStopPropagation;
            handler.call(element, e);
        });
        return element;
    }

    function oldIEPreventDefault() {
        this.returnValue = false;
    }

    function oldIEStopPropagation() {
        this.cancelBubble = true;
    }

    div = document.createElement('div');
    if (div.addEventListener) {
        div = undefined;
        return standardHookEvent;
    }
    if (div.attachEvent) {
        div = undefined;
        return oldIEHookEvent;
    }
    throw "Neither modern event mechanism (addEventListener nor attachEvent) is supported by this browser.";
})();

hookEvent(document.getElementById("hd_vertical"), "click", function(e) {
    // Event handling code
});

var _url = document.querySelectorAll("." + id)[1].getAttribute('href'); // Grabs the second matching element
var _url = document.querySelector("." + id).getAttribute('href'); // Grabs the first matching element