function SDMenu(id) {
	if (!document.getElementById || !document.getElementsByTagName)
		return false;
	this.menu = document.getElementById(id);
	this.submenus = this.menu.getElementsByTagName("div");
	this.remember = false;
	this.speed = 8;
	this.markCurrent = true;
	this.oneSmOnly = true;
}


SDMenu.prototype.init = function() {
	var mainInstance = this;
	for (var i = 0; i < this.submenus.length; i++) {
		this.submenus[i].className = "collapsed";

		this.submenus[i].getElementsByTagName("span")[0].onmouseover = function() {
			mainInstance.toggleMenu(this.parentNode);
		};
	}
};

SDMenu.prototype.toggleMenu = function(submenu) {
	if (submenu.className == "collapsed") {
		this.expandMenu(submenu);
	} else {
		this.collapseMenu(submenu);
	}
};
SDMenu.prototype.expandMenu = function(submenu) {
	document.getElementById("sobrante").style.display = "block";
	var fullHeight = submenu.getElementsByTagName("span")[0].offsetHeight;

	var links = submenu.getElementsByTagName("a");

	for (var i = 0; i < links.length; i++)
		fullHeight += links[i].offsetHeight;

	var moveBy = Math.round(this.speed * links.length);
	
	var mainInstance = this;

	var intId = setInterval(function() {
		var curHeight = submenu.offsetHeight;
		var newHeight = curHeight + moveBy;
		if (newHeight < fullHeight) {
			var zonaScroll = newHeight - submenu.style.height;
			submenu.style.height = newHeight + "px";
		} else {
			clearInterval(intId);
			submenu.style.height = "";
			submenu.className = "";
			mainInstance.memorize();
		}
	}, 30);
	this.collapseOthers(submenu);
};
SDMenu.prototype.collapseMenu = function(submenu) {
	if (submenu.getElementsByTagName("span")[0].className != "current") {
		var minHeight = submenu.getElementsByTagName("span")[0].offsetHeight;
	
		var moveBy = Math.round(this.speed * submenu.getElementsByTagName("a").length);
		var mainInstance = this;
		var intId = setInterval(function() {
			var curHeight = submenu.offsetHeight;
			var newHeight = curHeight - moveBy;
			if (newHeight > minHeight) {
				submenu.style.height = newHeight + "px";
			} else {
				clearInterval(intId);
				submenu.style.height = "";
				submenu.className = "collapsed";
				mainInstance.memorize();
			}	
		}, 30);
	}
};
SDMenu.prototype.collapseOthers = function(submenu) {
	if (this.oneSmOnly) {
		for (var i = 0; i < this.submenus.length; i++)
			if (this.submenus[i] != submenu && this.submenus[i].className != "collapsed")
				this.collapseMenu(this.submenus[i]);
	}
};
SDMenu.prototype.expandAll = function() {
	var oldOneSmOnly = this.oneSmOnly;
	this.oneSmOnly = false;
	for (var i = 0; i < this.submenus.length; i++)
		if (this.submenus[i].className == "collapsed")
			this.expandMenu(this.submenus[i]);
	this.oneSmOnly = oldOneSmOnly;
};
SDMenu.prototype.collapseAll = function() {
	for (var i = 0; i < this.submenus.length; i++)
	if (this.submenus[i].className != "collapsed") {
		this.collapseMenu(this.submenus[i]);
	}
};
SDMenu.prototype.memorize = function() {
	if (this.remember) {
		var states = new Array();
		for (var i = 0; i < this.submenus.length; i++)
			states.push(this.submenus[i].className == "collapsed" ? 0 : 1);
		var d = new Date();
		d.setTime(d.getTime() + (30 * 24 * 60 * 60 * 1000));
		document.cookie = "sdmenu_" + encodeURIComponent(this.menu.id) + "=" + states.join("") + "; path=/";
	}
};