var images=new Array();
images[0]='websites_london.jpg';
images[1]='webApplications_london.jpg';
images[2]='website_consultancy_london.jpg';


function isImageOk(img) 
{
    if (!img.complete) 
    	return false;

    if (typeof img.naturalWidth != "undefined" && img.naturalWidth == 0) 
    	return false;

    return true;

}

function checkImages() {

	 r=0;
    for (var i = 0; i < images.length; i++) 
	    if (!isImageOk(document.getElementById('banner'+i))) 
	    	r++;
	    	
    if(r==0)
     return true;
    else
    	return false;

}


function showThis(objId)
{
	for (var i = 0; i < images.length; i++) 
	{
		if(objId == 'banner'+i)
			document.getElementById('banner'+i).style.visibility = 'visible';
		else
			document.getElementById('banner'+i).style.visibility = 'hidden';	
	}
}


var counter=1;
function cycleBanners(position)
{
	if(checkImages())
	{
		if(typeof(position)!= 'undefined')
			counter=position;
		else if(counter==images.length)
			counter=0;
	
		showThis('banner'+counter);
		counter++;
	}
}

self.setInterval("cycleBanners()",8000)