// Define global variables 
//================================
var timeout = 3500;
var featuring = new Array('hplc05','hplc04','wtc01','hplc03','eapc01');
var counter = 1;

function addLoadEvent(func)
{
    var oldonload = window.onload;
    if (typeof window.onload != 'function')
	{
        window.onload = func;
    }
	else
	{
        window.onload = function()
		{
			if (oldonload)
			{
				oldonload();
			}
			func();
		}
    }
}



// Initialization
//================================
function init()
{ 
	setVisible(featuring[0]);
	for (var i=1; i < featuring.length; ++i)
	{
		setHidden(featuring[i]);
	}	
	setHidden('balloon');
	setTimeout("rotateMarquee();", timeout);
}

addLoadEvent(init);

// Get correct style object for specified object 
//================================
function getStyleObject(objectId)
{
    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];
    }
	return false;    
}

// Toggles the layer visibility on 
//================================
function toggleVisibility(objId)
{ 
	var styleObject = getStyleObject(objId);
    if (styleObject)
	{
		value = styleObject.visibility;
		styleObject.visibility = (value == 'hidden')? 'visible': 'hidden';
		return true;
    }
	return false;
}

// Set the layer visibility to visible/hidden 
//================================
function setVisibility(objId, viz)
{ 
	var styleObject = getStyleObject(objId);
    if (styleObject)
	{
		styleObject.visibility = viz;
		return true;
    }
	return false;
}

function setVisible(objId) { return setVisibility(objId, 'visible'); }
function setHidden(objId) { return setVisibility(objId, 'hidden'); }

// Switch filmstrip 
//================================
function rotateMarquee()
{ 
	toggleVisibility(featuring[(counter == 0)?featuring.length-1:counter-1]);
	if (counter == (featuring.length))
	{
		counter = 0;
	}
	toggleVisibility(featuring[counter++]);
	setTimeout('rotateMarquee()', timeout);	
} 

// Custom Error Handler 
//================================
function errorHandler(desc,page,line,chr) 
{
	alert(
		'JavaScript error occurred! \n'
		+'\nError description: \t'+desc
		+'\nPage address:      \t'+page
		+'\nLine number:       \t'+line
 	);
 	return true;
}
window.onerror = errorHandler;