function revealOrHideTile (tileName, mode){
  if (mode == 1){
    document.getElementById(tileName).style.visibility = "visible";
  }
  if (mode == 0){
    document.getElementById(tileName).style.visibility = "hidden";
  }
}
function revealOrHideDifferentTile (tileName, mode){
  if (mode == 1){
    document.getElementById(tileName).style.visibility = "visible";
  document.getElementById(tileName).style.display = "block";
  }
  if (mode == 0){
    document.getElementById(tileName).style.visibility = "hidden";
  document.getElementById(tileName).style.display = "none";
  }
}

function toggleTile (hideTile, showTile){
  document.getElementById(hideTile).style.visibility = "hidden";
  document.getElementById(hideTile).style.display = "none";
  document.getElementById(showTile).style.visibility = "visible";
  document.getElementById(showTile).style.display = "block";
}
function revealAndToggleTiles (tileName, mode, hideTile, showTile){
  revealOrHideTile (tileName, mode);
  toggleTile (hideTile, showTile);
}

function showLetter(mode){
  if (mode == 0){
    centerTile ('videoTile');
    document.getElementById('videoTile').style.visibility = "visible";
    document.getElementById('videoTile').style.zIndex = "2";
    document.getElementById('division1').style.opacity = "0.4";
    document.getElementById('division1').style.filter = "alpha(opacity:40)";
    document.getElementById('linkPanel').style.opacity = "0.4";
    document.getElementById('linkPanel').style.filter = "alpha(opacity:40)";
  }
  if (mode == 1){
    document.getElementById('videoTile').style.visibility = "hidden";
    document.getElementById('videoTile').style.zIndex = "-1";
    document.getElementById('division1').style.opacity = "1";
    document.getElementById('division1').style.filter = "alpha(opacity:100)";
    document.getElementById('linkPanel').style.opacity = "1";
    document.getElementById('linkPanel').style.filter = "alpha(opacity:100)";
  }
}

function showTile(tileName, mode){
  if (mode == 0){
    centerTile (tileName);
    document.getElementById(tileName).style.visibility = "visible";
    document.getElementById(tileName).style.zIndex = "2";
    document.getElementById('division1').style.opacity = "0.4";
    document.getElementById('division1').style.filter = "alpha(opacity:40)";
    document.getElementById('linkPanel').style.opacity = "0.4";
    document.getElementById('linkPanel').style.filter = "alpha(opacity:40)";
  }
  if (mode == 1){
    document.getElementById(tileName).style.visibility = "hidden";
    document.getElementById(tileName).style.zIndex = "-1";
    document.getElementById('division1').style.opacity = "1";
    document.getElementById('division1').style.filter = "alpha(opacity:100)";
    document.getElementById('linkPanel').style.opacity = "1";
    document.getElementById('linkPanel').style.filter = "alpha(opacity:100)";
  }
}

// FOUND AT GEEKDAILY - THIS MAN / WOMAN IS A GENIUS!!
// http://www.geekdaily.net/2007/07/04/javascript-cross-browser-window-size-and-centering/
function centerTile (tileToBePositioned){
	var Element = document.getElementById(tileToBePositioned); 
  var objh = parseFloat(Element.style.height)/2; 
  var objw = parseFloat(Element.style.width)/2;
	
	// WINDOW SIZE
	var w = 0;
	var h = 0;

	//IE
	if(!window.innerWidth){
		//strict mode
		if(!(document.documentElement.clientWidth == 0)){
			w = document.documentElement.clientWidth;
			h = document.documentElement.clientHeight;
		}
		//quirks mode
		else{
			w = document.body.clientWidth;
			h = document.body.clientHeight;
		}
	}
	//w3c
	else{
		w = window.innerWidth;
		h = window.innerHeight;
	}
	
	// SCROLL POSITION
	var offsetX = 0;
	var offsetY = 0;

	//IE
	if(!window.pageYOffset){
		//strict mode
		if(!(document.documentElement.scrollTop == 0)){
			offsetY = document.documentElement.scrollTop;
			offsetX = document.documentElement.scrollLeft;
		}
		//quirks mode
		else{
			offsetY = document.body.scrollTop;
			offsetX = document.body.scrollLeft;
		}
	}
	//w3c
	else{
		offsetX = window.pageXOffset;
		offsetY = window.pageYOffset;
	}
	
	//var data = "                DATA              \n";
	//data = data + "element size: height = "+objh+", width = "+objw+" \n";
	//data = data + "window size: height = "+h+", width = "+w+" \n";
	//data = data + "document size: height = "+offsetY+", width = "+offsetX+"\n";
	//data = data + "top = "+h+"/2 + "+offsetY+" - "+objh+"\n";
	//data = data + "left = "+w+"/2 + "+offsetX+" - "+objw+"\n";
	//alert (data);
	
	var yPosition = Math.floor(Math.round((h/2)+offsetY)-objh);
	var xPosition = Math.floor(Math.round((w/2)+offsetX)-objw);
	if (yPosition < 0){
		Element.style.top =  '0px';
	}
	else{
		Element.style.top =  yPosition+'px';
	}
	if (xPosition < 0){
		Element.style.left = '0px';
	}
	else{
		Element.style.left = xPosition+'px';
	}
}