function addEvent(obj, evType, fn){
    if (obj.addEventListener){
        obj.addEventListener(evType, fn, false);
        return true;
    } else if (obj.attachEvent){
        var r = obj.attachEvent("on"+evType, fn);
        return r;
    } else {
        return false;
    }
}

function removeEvent(obj, evType, fn, useCapture){
    if (obj.removeEventListener){
        obj.removeEventListener(evType, fn, useCapture);
        return true;
    } else if (obj.detachEvent){
        var r = obj.detachEvent("on"+evType, fn);
        return r;
    } else {
        alert("Handler could not be removed");
    }
}

/**
 * Code below taken from - http://www.evolt.org/article/document_body_doctype_switching_and_more/17/30655/
 *
 * Modified 4/22/04 to work with Opera/Moz (by webmaster at subimage dot com)
 *
 * Gets the full width/height because it's different for most browsers.
 */

function getViewportHeight() {
    if (window.innerHeight!=window.undefined) return window.innerHeight;
    if (document.compatMode=='CSS1Compat') return document.documentElement.clientHeight;
    if (document.body) return document.body.clientHeight; 
    return window.undefined; 
}

function getViewportWidth() {
    var offset = 17;
    var width = null;
    if (window.innerWidth!=window.undefined) return window.innerWidth; 
    if (document.compatMode=='CSS1Compat') return document.documentElement.clientWidth; 
    if (document.body) return document.body.clientWidth; 
}

/**
 * Gets the real scroll top
 */

function getScrollTop() {
    if (self.pageYOffset) // all except Explorer
    {
        return self.pageYOffset;
    }
    else if (document.documentElement && document.documentElement.scrollTop)
    // Explorer 6 Strict
    {
        return document.documentElement.scrollTop;
    }
    else if (document.body) // all other Explorers
    {
        return document.body.scrollTop;
    }
}

function getScrollLeft() {
    if (self.pageXOffset) // all except Explorer
    {
        return self.pageXOffset;
    }
    else if (document.documentElement && document.documentElement.scrollLeft)
    // Explorer 6 Strict
    {
        return document.documentElement.scrollLeft;
    }
    else if (document.body) // all other Explorers
    {
        return document.body.scrollLeft;
    }
}