function getLayerStyle(lyrId) {
	var el = (document.getElementById)? document.getElementById(lyrId) : document.all[lyrId];
	if (!el) return null;
	return (el.style)? el.style : el;
}

function showLayer(lyrId, display) {
	var lyr = getLayerStyle(lyrId);
	if (!lyr) return;
	
	lyr.visibility = 'visible';
	lyr.display = (display)? display : 'block';
}

function hideLayer(lyrId) {
	var lyr = getLayerStyle(lyrId);
	if (!lyr) return;
	lyr.visibility = 'hidden';
	lyr.display = 'none';
}


var currentPebble = null;
function pebble_highlight(pebId) {
	if (currentPebble) {
		hideLayer(currentPebble);
	}
	if (pebId) {
		showLayer(pebId, 'inline');
		currentPebble = pebId;
	}
}