function getStyleObject(objectId) {
  // cross-browser function to get an object's style object given its id
  if (document.getElementById && document.getElementById(objectId)) {
    // W3C DOM
    return document.getElementById(objectId).style;
  } else if (document.all && document.all(objectId)) {
    // MSIE 4 DOM
    return document.all(objectId).style;
  } else if (document.layers && document.layers[objectId]) {
    // NN 4 DOM.. note: this won't find nested layers
    return document.layers[objectId];
  } else {
    return false;
  }
}

function elementById(objectId) {
  // cross-browser function to get an object's style object given its id
  if(document.getElementById && document.getElementById(objectId)) {
    // W3C DOM
    return document.getElementById(objectId);
  } else if (document.all && document.all(objectId)) {
    // MSIE 4 DOM
    return document.all(objectId);
  } else if (document.layers && document.layers[objectId]) {
    // NN 4 DOM.. note: this won't find nested layers
    return document.layers[objectId];
  } else {
    return false;
  }
}

function setVisibile(objectId, newVisibility) {
    // get a reference to the cross-browser style object and make sure the object exists
    var styleObject = getStyleObject(objectId);
    if(styleObject) {
	styleObject.visibility = newVisibility;
	return true;
    } else {
	// we couldn't find the object, so we can't change its visibility
	return false;
    }
}