/* Menu de licencia de uso libre obtenido de: http://www.leigeber.com/2008/11/drop-down-menu/
	autor: Michael Leigeber www.leigeber.com
	fecha de realización: Noviembre 24,2008 
	Se conserva el código original para este proyecto
	*/
	
var menu = function() {
	var t = 15, z = 50, s = 6, a;
	function dd(n) { this.n = n; this.h = []; this.c = [] }
	dd.prototype.init = function(p, c) {
		a = c; 
		var w = document.getElementById(p);
		var s = w.getElementsByTagName('ul'); 
		var l = s.length;
		var i = 0;
		for(i; i < l; i++){
			var h = s[i].parentNode; 
			this.h[i] = h;
			this.c[i] = s[i];
			h.onmouseover = new Function(this.n+'.st(' + i + ', true)');
			h.onmouseout = new Function(this.n+'.st(' + i + ')');
		}
	}
	dd.prototype.st = function(x, f){
		var c = this.c[x]; 
		var h = this.h[x]; 
		var p = h.getElementsByTagName('a')[0];
		clearInterval(c.t);
		c.style.overflow = 'hidden';
		if(f) {
			p.className += ' ' + a;
			if(!c.mh) {
				c.style.display = 'block';
				c.style.height = '';
				c.mh = c.offsetHeight;
				c.style.height = 0;
			}
			if(c.mh == c.offsetHeight) {
				c.style.overflow = 'visible'
			}
			else {
				c.style.zIndex = z;
				z++;
				c.t = setInterval(
								  	function(){
											sl(c, 1)
									}
								,t);
			}
		} else {
			p.className = p.className.replace(a, ' ');
			c.t = setInterval( 
							  function() {
										sl(c,-1)
										} ,t
							  )
			}
	}
	function sl(c,f){
		var h = c.offsetHeight;
		if((h <= 0 && f != 1) || ( h >= c.mh && f == 1)) {
			if(f == 1) {
				c.style.filter = '';
				c.style.opacity = 1;
				c.style.overflow = 'visible';
			}
			clearInterval(c.t);
			return
		}
		var d = (f == 1)? Math.ceil((c.mh - h) / s) : Math.ceil( h / s);
		var o = h/c.mh;
		c.style.opacity = o;
		c.style.filter = 'alpha(opacity = ' + (o * 100) + ')';
		c.style.height = h + (d * f) + 'px'
	}
	return{dd:dd}
}();