// get browser type
var agent = navigator.userAgent.toLowerCase();
var is_ie = ((agent.indexOf("msie") != -1) && (agent.indexOf("opera") == -1));

// main javascript functions

function galleryLink(link) {
	var links = get_links();
	document.location = links[link];
}

// show info for gallery section that mouse is over
function showGalleryInfo(gallery_section, map, description_text) {
	var descriptions = get_descriptions();
	var description_text = descriptions[gallery_section];

	// get description table cell: upper_level_description, main_level_description, lower_level_description
	description = document.getElementById(map + '_description');

	// uncomment to display gallery descritpions on mouseover
	//description.innerHTML = description_text;
}


function highlight_nav(nav_id, drop_box_id, this_drop_down) {
	var nav = document.getElementById(nav_id);
	nav.style.color='#FFFFFF';

	var drop_box = document.getElementById(drop_box_id);
	drop_box.style.backgroundImage='url(/images/nav_bar_background.gif)';
	drop_box.style.backgroundRepeat='no-repeat';

	this_drop_down.style.backgroundImage = 'url(/images/nav_bar_background.gif)';
	this_drop_down.style.backgroundRepeat='no-repeat';
	if (this_drop_down.childNodes[0].style) {
		this_drop_down.childNodes[0].style.color = '#FFFFFF';
	}
}

function unhighlight_nav(nav_id, drop_box_id, this_drop_down) {
	var nav = document.getElementById(nav_id);
	nav.style.color='#460708';

	var drop_box = document.getElementById(drop_box_id);
	drop_box.style.backgroundImage='';

	this_drop_down.style.color='#460708';
	this_drop_down.style.backgroundImage = '';
	if (this_drop_down.childNodes[0].style) {
		this_drop_down.childNodes[0].style.color = '#602F2B';
	}
}


var timer = 0;
var drop_down = "";

var drop_down_timer = 0;
var drop_down_timer_subs = 0;

var all_drop_downs = new Array();
all_drop_downs.push("drop_box1");
all_drop_downs.push("drop_box2");
all_drop_downs.push("drop_box3");
all_drop_downs.push("volunteer");
all_drop_downs.push("volunteer2");
all_drop_downs.push("drop_box4");
all_drop_downs.push("drop_box5");
all_drop_downs.push("drop_box6");
all_drop_downs.push("swap");
all_drop_downs.push("programs");
all_drop_downs.push("education_exhibitions");
all_drop_downs.push("drop_box7");
all_drop_downs.push("drop_box8");
all_drop_downs.push("drop_box9");

function show_drop_down(menu) {
	drop_down = document.getElementById(menu + "_drop_down");

	drop_down.style.left = getMenuX(menu);
	drop_down.style.top = getMenuY(menu);

	drop_down.style.visibility = 'visible';

	// hide all other drop down menus
	for (var i in all_drop_downs) {
		if (menu != all_drop_downs[i]) {
			if (menu == "volunteer" && all_drop_downs[i] == "drop_box1" ||
				menu == "drop_box1" && all_drop_downs[i] == "volunteer") {
				continue;
			}

			if (menu == "volunteer2" && all_drop_downs[i] == "drop_box3" ||
				menu == "drop_box3" && all_drop_downs[i] == "volunteer2") {
				continue;
			}

			if (menu == "programs" && all_drop_downs[i] == "drop_box6" ||
				menu == "drop_box6" && all_drop_downs[i] == "programs") {
				continue;
			}

			if (menu == "swap" && all_drop_downs[i] == "drop_box6" ||
				menu == "drop_box6" && all_drop_downs[i] == "swap") {
				continue;
			}

			if (menu == "education_exhibitions" && all_drop_downs[i] == "drop_box6" ||
				menu == "drop_box6" && all_drop_downs[i] == "education_exhibitions") {
				continue;
			}


			drop_down = document.getElementById(all_drop_downs[i] + "_drop_down");

			if (drop_down != null) {
				drop_down.style.visibility = 'hidden';
			}
		}
	}

	clearTimeout(drop_down_timer);
}

function hide_drop_down(menu) {
	drop_down = document.getElementById(menu + "_drop_down");
	drop_down_timer = setTimeout("drop_down.style.visibility = 'hidden';", 50);
}

function hide_drop_down_immediate(menu) {
	drop_down = document.getElementById(menu + "_drop_down");
	drop_down.style.visibility = 'hidden';
}

function getMenuX(element_id){
	var xPos = document.getElementById(element_id).offsetLeft;
	var tempEl = document.getElementById(element_id).offsetParent;

	while (tempEl != null) {
		xPos += tempEl.offsetLeft;
		tempEl = tempEl.offsetParent;
	}

	if (element_id == "swap" || element_id == "programs" || element_id == "education_exhibitions" || element_id == "volunteer" || element_id == "volunteer2") {
		xPos = xPos + 72;

		if (is_ie) {
			xPos = xPos - 2;
		}
	}

	xPos = xPos + 151;

	return xPos;
}

function getMenuY(element_id) {
	var header = document.getElementById("header");
	var navbar = document.getElementById("navbar");

	var yPos = document.getElementById(element_id).offsetTop;
	var tempEl = document.getElementById(element_id).offsetParent;

	while (tempEl != null) {
		yPos += tempEl.offsetTop;
		tempEl = tempEl.offsetParent;
	}

	// vertical offset for submenus
	var isSubMenu = false;
	if (element_id == "volunteer"
			|| element_id == "volunteer2"
			|| element_id == "programs"
			|| element_id == "swap"
			|| element_id == "education_exhibitions") {
		isSubMenu = true;
	}

	if (isSubMenu) {
		yPos = yPos - 5;
	}

	return yPos;
}