document.onmousemove = updateMousePos;

mousex = 0;
mousey = 0;

function updateMousePos(e)
{
  mousex = (document.all) ? window.event.x + document.body.scrollLeft : e.pageX;
  mousey = (document.all) ? window.event.y + document.body.scrollTop  : e.pageY;  
}

tooltip = null;

function showToolTip(text)
{
  if (tooltip != null)
  {
    hideToolTip();
  }

  tooltip = document.getElementById(text);

  if (tooltip == null)
  {
    tooltip = document.createElement("div");
    tooltip.className = "tooltip";
    tooltip.id = text;
    tooltip.appendChild(document.createTextNode(text));
    document.body.appendChild(tooltip);
  }

  tooltip.style.left = (mousex + 10) + "px";
  tooltip.style.top  = (mousey + 10) + "px";
  tooltip.style.display = "block";
}

function hideToolTip() 
{
  if (tooltip != null)
  {
    tooltip.style.display = "none";
  }
  tooltip = null;
}