//------------------------------
// Returns the element with the given id, or null if none.
//
function ZGElementById(pId) {
    if (document.getElementById) {
        return document.getElementById(pId);
    }
    else if (document.all) {
        return document.all[pId];
    }
    else if (document.layers) {
        return document.layers[pId];
    }
    else {
	return null;
    }
}

//------------------------------
// Show the given element.
//
function ZGShowElement(pElem) {
    if (pElem == null) { return null }
    pElem.style.display = 'block';
    return null;
}

//------------------------------
// Hide the given element.
//
function ZGHideElement(pElem) {
    if (pElem == null) { return null }
    pElem.style.display = 'none';
    return null;
}

//------------------------------
// Show the given callout.
//
function ZGShowCallout(pCalloutId) {
    ZGShowElement(ZGElementById("callout-" + pCalloutId));
}

//------------------------------
// Hide the given callout.
//
function ZGHideCallout(pCalloutId) {
    ZGHideElement(ZGElementById("callout-" + pCalloutId));
}

// end of file