This is my HTML code:
I would do something like this
DEMO in JsBin: http://jsbin.com/ofiqur/1/
Click Here
and in jQuery as simple as
var min = "-100px", // remember to set in css the same value
max = "0px";
$(function() {
$("#showmenu").click(function() {
if($(".menu").css("marginLeft") == min) // is it left?
$(".menu").animate({ marginLeft: max }); // move right
else
$(".menu").animate({ marginLeft: min }); // move left
});
});