本博客运行了多久?

<!-- run -->
<style>
  #app{
  color: red;
  }
</style>
<div id="app">
</div>

<script type="text/javascript">
var webstar= new Date("8/13/2015"); 
var webnow = new Date();
var dotime = webnow.getTime() - webstar.getTime();
var donow = Math.floor(dotime / (1000 * 60 * 60 * 24));
document.getElementById('app').innerText = '本博客已稳定运行了'+ donow +'天'
</script>