function findPosX(obj){
	var curleft = 0;
	if (obj.offsetParent)
	{
		while (obj.offsetParent)
		{
			curleft += obj.offsetLeft
			obj = obj.offsetParent;
		}
	}
	else if (obj.x)
		curleft += obj.x;
	return curleft;
}

function findPosY(obj){
	var curtop = 0;
	if (obj.offsetParent)
	{
		while (obj.offsetParent)
		{
			curtop += obj.offsetTop
			obj = obj.offsetParent;
		}
	}
	else if (obj.y)
		curtop += obj.y;
	return curtop;
}

function descr_popup(pos){
    var images = document.getElementsByTagName('img');
    for (i = 0 ; i < images.length ; i++){
        for (key in descriptions){
           if (key == images.item(i).id){
                images.item(i).onmouseover = function(){
                    var desc = document.createElement("div");
                    var element = this;
                    desc.style.position		= "absolute";
                    desc.id					= "description_window";
                    desc.style.visibility	= "visible";
                    desc.style.background	= "lightyellow";
                    desc.style.width		= "170px";
                    desc.style.padding		= "7px";
                    desc.style.fontSize		= "12px";
                    desc.style.border		= "1px solid #195F81";
                    desc.style.left			= findPosX(element) + parseInt(5) + element.width + "px";
                    desc.style.top			= findPosY(element) + element.height + "px";

                    document.body.appendChild(desc);

                    var desc_div = document.createElement("div");
                    desc_div.id     = "explain";
                    desc_div.innerHTML = descriptions[this.id];
                    desc.appendChild(desc_div);
                }
                
                images.item(i).onmouseout = function(){
                    var desc = document.getElementById('description_window');
                    if (desc != null)
                        document.body.removeChild(desc);
                }
		    }
        }
    }
}