function dimPreviews() {
	document.getElementById('previews').className = 'previewsdim';
}

function clearPreviews() {
	document.getElementById('previews').className = 'previews';
}

function loadPic(fileName){
  // Dim Preview pictures
  dimPreviews();
  
  // Show mainpic and controller
  imgElt=document.getElementById('mainpic');
  contrElt=document.getElementById('controller');
  imgElt.style.display = 'block';
  contrElt.style.display = 'block';
  
  // Assign source file to picture
  imgElt.src='mb08pics/images/img/' + fileName;
  
  // Add event handler
  imgElt.onclick = closePic;
}

function closePic(){
	// Clear up preview pictures
	clearPreviews();
	
	// Hide mainpic and controller
	imgElt=document.getElementById('mainpic');
	contrElt=document.getElementById('controller');
	imgElt.style.display = 'none';
	contrElt.style.display = 'none';
}

function findPrevPic(){
	imgElt=document.getElementById('mainpic');
	var currentFilename = imgElt.src.replace(/.*\//,'')
	var x = document.getElementsByTagName("img");
	for (var i=2; i < x.length; i++){
		if (x[i].src.replace(/.*\//,'') == currentFilename){
			return x[i-1].src.replace(/.*\//,'');
		}
	}
}

function findNextPic(){
	imgElt=document.getElementById('mainpic');
	var currentFilename = imgElt.src.replace(/.*\//,'')
	var x = document.getElementsByTagName("img");
	for (var i=0; i < x.length-2; i++){
		if (x[i].src.replace(/.*\//,'') == currentFilename){
			return x[i+1].src.replace(/.*\//,'');
		}
	}
}

function loadPrevPic(){
	if (findPrevPic()) {
		loadPic(findPrevPic());
	}
}

function loadNextPic(){
	if (findNextPic()) {
		loadPic(findNextPic());
	}
}