//change gallery item
function changeGalleryItem(elem, picId){
	//hide all normal pics
	normalPics = $$('.normalPics');
	for (i=0; i<normalPics.length;i++){
		normalPics[i].style.display = "none";
	}
	//display normal pic for request Id
	$("normalPic"+picId).style.display = "block";  
	//hide all description texts
	descriptionTexts = $$('.descriptionText');
	for (i=0; i<descriptionTexts.length;i++){
		descriptionTexts[i].style.display = "none";
	}
	//display description text for request Id
	$("descriptionText"+picId).style.display = "block"; 
	//changed all thumbnails border
	thumbnailPics = $$('.thumbnailPics');
	for (i=0; i<thumbnailPics.length;i++){
		thumbnailPics[i].className = "thumbnailPics";
	}
	//set current thumbnail border
	elem.className = "thumbnailPics thumbnailPicsFrame";
}