dupre,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css"> #main .openclosebtn{
background-color: #228B22;
color: #FFFFFF;
padding: 5px 12px;
}
</style>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script>
$(function() {
$('.openclosebtn, html').click(function(event){
var btn = $('.openclosebtn'), status = !btn.data('status');
if ($(this).is(btn) && status) {
event.stopPropagation();
btn.html('Close')
.data('status', status);
}
else {
btn.html('Меню')
.data('status', false);
}
});
});
</script>
</head>
<body>
<div id="main">
<span class="openclosebtn">Меню</span>
</div>
</body>
</html>