var ORANGE_MIN = 35;
var ORANGE_MAX = 365;
var ORANGE_RANGE = ORANGE_MAX - ORANGE_MIN;

var TAB_ITEM = document.getElementById('orange-bug');
var UP_BUTTON = document.getElementById('up-button');
var DOWN_BUTTON = document.getElementById('down-button');
var GAL_BODY = document.getElementById("gallery-scroller");

var TIMEOUT_HOLDER;

function startMove(inc)
{
	TIMEOUT_HOLDER = setInterval('move(' + inc + ')', 5);
}

function move(inc)
{
	GAL_BODY.scrollTop += inc;
	setIndicator();
}

function setIndicator()
{
	var bodyHeight = GAL_BODY.scrollHeight - GAL_BODY.clientHeight;
	var orangeTop = parseInt(ORANGE_RANGE * (GAL_BODY.scrollTop / bodyHeight)) + 35;
	TAB_ITEM.style.top = orangeTop + "px";
}

function stopMove()
{
	clearInterval(TIMEOUT_HOLDER);
}