css push div down
<style>
div{border:1px solid red}
#container{height:1000px;}
#inner-container{position:absolute;bottom:0px;}
.inner {height:200px;width:200px;margin:5px;;
</style>
<div id="container">
<div id="inner-container">
<div class="inner"></div>
<div class="inner"></div>
<div class="inner"></div>
</div>
</div>