Untitled

<script src="http://cdnjs.cloudflare.com/ajax/libs/gsap/latest/TweenMax.min.js"></script>
    <style type="text/css">
    .box {
      margin: 0px;
      height: 50px;
      width: 50px;
      background-color: blue;
        }
    li {list-style: none;}
    .inner {margin-left: -40px; display: block;}
    .inner li, .box {display: block;}

    #outer li { display: inline-block;}
    </style>
</head>
<body>
<ul id="outer">
    <li><button type="button" class="toggle" name="btn1">Open</button>
        <ul class="inner">
            <li><div class="box"></div></li>
        </ul>
    </li><!-- end of outer li  -->
    <li><button type="button" class="toggle" name="btn2">Open</button>
        <ul class="inner">
                <li><div class="box"></div></li>
        </ul>
    </li>  <!-- end of outer li -->
</ul>  <!-- end of outer -->
<script>

var menu = document.getElementsByClassName('box');
var btn = document.getElementsByClassName('toggle');

 function move_box(e) {
   if(this.innerHTML === 'Open') {
        TweenLite.to(menu[i], 2, {y: 100, ease:Power2.easeOut});
    this.innerHTML = 'Close';
    } else {
    TweenLite.to(menu[i], 2, {y: 0, ease:Power2.easeOut});
    this.innerHTML = 'Open';
      }
    }

for (var i = 0; i < btn.length; i++ ) {
    btn[i].addEventListener("click", move_box, false);
}


</script>
</body>

TweenLite.to(menu[btn.indexOf(this)], 2, {y: 100, ease:Power2.easeOut});

var btn = document.getElementsByClassName('toggle');

function move_box(e) {
    if (this.innerHTML === 'Open') {
        TweenLite.to(this.parentNode.getElementsByClassName('box')[0], 2, { y: 100, ease: Power2.easeOut });
        this.innerHTML = 'Close';
    } else {
        TweenLite.to(this.parentNode.getElementsByClassName('box')[0], 2, { y: 0, ease: Power2.easeOut });
        this.innerHTML = 'Open';
    }
}

for (var i = 0; i < btn.length; i++) {
    btn[i].addEventListener("click", move_box, false);
}

<script>
var i;
var menu = document.getElementsByClassName('box');
var btn = document.getElementsByClassName('toggle');

 function move_box(e) {
        var j;

        var id = this.getAttribute("id");
        j = id.substr(3,1); //get digit at end of id.
            if(this.innerHTML === 'Open') {
            TweenLite.to(menu[j], 2, {y: 100, ease:Power2.easeOut});
        this.innerHTML = 'Close';
        } else {
        TweenLite.to(menu[j], 2, {y: 0, ease:Power2.easeOut});
        this.innerHTML = 'Open';
          }
    }

for ( i = 0; i < btn.length; i++ ) {
    btn[i].addEventListener("click", move_box, false);
    btn[i].setAttribute("id", "btn" + i);
}

</script>