function getViewportWidth(){
	var viewportwidth;
	
	if (typeof window.innerWidth != 'undefined')
	{
		viewportwidth = window.innerWidth;
	}
	else if (typeof document.documentElement != 'undefined'
		&& typeof document.documentElement.clientWidth !=
		'undefined' && document.documentElement.clientWidth != 0)
	{
		viewportwidth = document.documentElement.clientWidth;
	} 
	else
	{
		viewportwidth = document.getElementsByTagName('body')[0].clientWidth;
	}	
	return viewportwidth;
}

function getViewportHeight(){
	var viewportheight;
 
	if (typeof window.innerWidth != 'undefined')
	{
	  viewportheight = window.innerHeight;
	}	
	else if (typeof document.documentElement != 'undefined'
	 && typeof document.documentElement.clientWidth !=
	 'undefined' && document.documentElement.clientWidth != 0)
	{
	   viewportheight = document.documentElement.clientHeight;
	}	
	else
	{
	   viewportheight = document.getElementsByTagName('body')[0].clientHeight;
	}
	return viewportheight;
}

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