function getPageCenter(){
	//alert(document.body.clientHeight);
	window.scrollTo(0, document.documentElement.clientHeight);

}

function call_lightbox(imageArrayPHP){
	if(imageArrayPHP==undefined || imageArrayPHP=='') return false;
	
	imageArray = [];
	for (var i=0; i<imageArrayPHP.length; i+=2){
		if (imageArrayPHP[i]!=''){
			imageArray.push(new Array(imageArrayPHP[i], imageArrayPHP[i+1]));
		}
	}
	
	
	
	hideSelectBoxes();
	hideFlash(); 
	// stretch overlay to fill page and fade in
	var arrayPageSize = getPageSize();
	Element.setWidth('stimuli_overlay', arrayPageSize[0]);
	Element.setHeight('stimuli_overlay', arrayPageSize[1]);
	new Effect.Appear('stimuli_overlay', { duration: overlayDuration, from: 0.0, to: overlayOpacity });
	imageNum = 0;		
	if (!document.getElementsByTagName){ return; }
	imageArray.removeDuplicates();
	//while(imageArray[imageNum][0] != imageLink.getAttribute('href')) { imageNum++;}
	// calculate top and left offset for the lightbox 
	var arrayPageScroll = getPageScroll();
	var lightboxTop = arrayPageScroll[1] + (arrayPageSize[3] / 10);
	var lightboxLeft = arrayPageScroll[0];
	Element.setTop('stimuli_lightbox', lightboxTop);
	Element.setLeft('stimuli_lightbox', lightboxLeft);
	Element.show('stimuli_lightbox');
	myLightbox.changeImage(imageNum);
}