// Returns rectangular and center
// coordinates of renderable display

function getDisplayDims(CANVAS) {
  var CWidth, CHeight, CScrollX, CScrollY;

  if (isNS) {
    CWidth = self.innerWidth;
    CHeight = self.innerHeight;
    CScrollX = window.pageXOffset;
    CScrollY = window.pageYOffset;
  } else if (isgteIE6) {
    CWidth = document.documentElement.clientWidth;
    CHeight = document.documentElement.clientHeight;
    if (CWidth==0) {
      CWidth = document.body.clientWidth;
      CHeight = document.body.clientHeight;
    }
    CScrollX = document.body.scrollLeft +
               document.documentElement.scrollLeft;
    CScrollY = document.body.scrollTop +
               document.documentElement.scrollTop;
  } else if (isIE) {
    CWidth = document.body.clientWidth;
    CHeight = document.body.clientHeight;
    CScrollX = document.body.scrollLeft;
    CScrollY = document.body.scrollTop;
  }
  CANVAS.Left    = CScrollX;
  CANVAS.Right   = CWidth + CScrollX;
  CANVAS.Top     = CScrollY;
  CANVAS.Bottom  = CHeight + CScrollY;
  CANVAS.xMiddle = Math.round(CWidth/2) + CScrollX;
  CANVAS.yMiddle = Math.round(CHeight/2) + CScrollY;
}

var Canvas = new Object();

// Return element pointer

function getEPtr(ID) {
  return isNS4 ? document.layers[ID] :
        (isIE4 ? document.all[ID].style :
                 document.getElementById(ID).style);
}

// Returns passed element's current X positon

function getXpos(N) {
  return parseInt(getEPtr(N).left);
}

// Returns passed element's current Y positon

function getYpos(N) {
  return parseInt(getEPtr(N).top);
}

  coordX = getXpos(styleTagID);
  coordY = getYpos(styleTagID);
  e = getEPtr(styleTagID);

  if (isDOM2 || isIE4) {
    if (coordX < Canvas.Left   ||
        coordX > Canvas.Right  ||
        coordY < Canvas.Top    ||
        coordY > Canvas.Bottom)
      e.display = "none";
    else
      e.display = "inline";
  }