var MainMenu = {

	/*Be careful : menuLeftMargin has to be left margin of #page #header #tabs #menu*/
	menuLeftMargin : 290,

	expand: function(elm) {
		elm.getElementsByTagName("div")[0].style.left = (MainMenu.getposOffset(elm, "left") - MainMenu.getposOffset(document.getElementById("tabs"), "left") - MainMenu.menuLeftMargin - 20) + "px";
		elm.getElementsByTagName("div")[0].style.display = "block";
	},

	reduce: function(elm) {
		elm.getElementsByTagName("div")[0].style.display = "none";
	},

	getposOffset: function(what, offsettype){
		var totaloffset=(offsettype=="left")? what.offsetLeft : what.offsetTop;
		var parentEl=what.offsetParent;
		while (parentEl!=null){
			totaloffset=(offsettype=="left")? totaloffset+parentEl.offsetLeft : totaloffset+parentEl.offsetTop;
			parentEl=parentEl.offsetParent;
		}
		return totaloffset;
	}
}