var mousePos;
document.onmousemove = mouseMove; 
function mouseMove(ev){ 
    ev           = ev || window.event; 
    mousePos = mouseCoords(ev); 
}
function mouseCoords(ev){ 
    if(ev.pageX || ev.pageY){ 
        return {x:ev.pageX, y:ev.pageY}; 
    } 
    return { 
        x:ev.clientX + document.body.scrollLeft - document.body.clientLeft, 
        y:ev.clientY + document.body.scrollTop  - document.body.clientTop 
    }; 
} 
function showBB ( nom )
{
	elt = document.getElementById(nom);
	elt.style.visibility='visible';
	elt.style.left = mousePos.x + 10;
	elt.style.top = mousePos.y + 10 ;
	return true;
}
function hideBB ( nom )
{
	elt = document.getElementById(nom);
	elt.style.visibility='hidden';
}