<!-- css按钮样式 -->
<style type="text/css">
.div_right_bottom {    
    -moz-box-shadow:inset 0px 1px 0px 0px #ffffff;    
    -webkit-box-shadow:inset 0px 1px 0px 0px #ffffff;    
    box-shadow:inset 0px 1px 0px 0px #ffffff;    
    background-color:#f9f9f9;    
    -moz-border-radius:6px;    
    -webkit-border-radius:6px;    
    border-radius:6px;    
    border:1px solid #dcdcdc;    
    display:inline-block;    
    cursor:pointer;    
    color:#666666;    
    font-family:Arial;    
    font-size:15px;    
    font-weight:bold;    
    padding:7px 14px;    
    text-decoration:none;    
    text-shadow:0px 1px 0px #ffffff;
    float:right;
    position:fixed;
    right:10px;
    bottom:5px;
    z-index:20;
    _position:absolute; 
}
.div_right_bottom:hover { background-color:#e9e9e9; }
</style>

<!-- 原生js -->
<script>
function index_toc() {
    var toc=document.getElementsByClassName('toc');
    if(0<toc.length) {
        toc[0].scrollIntoView();
    } else {
        document.getElementsByClassName('post-title')[0].scrollIntoView();
        }
}
</script>

<!-- html按钮 -->
  <div class="div_right_bottom">
   <a href="javascript:index_toc()">回到索引</a>
  </div>