固定于底部的图片返回按钮

#idBack{
position: absolute;
bottom: 15px;
right: 15px;
}

<div id= 'idBack' style="background-color:transparent;">
<a href="javascript:history.go(-1)" target="_self">
<img class="img-circle" src="img/arrow_left.png" alt="back" style=" width: 60px;opacity:0.8;"/>
</a>
</div>