datepicker dates before yesterday disabled

HTML

<script src="//netdna.bootstrapcdn.com/bootstrap/3.0.3/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.0.3/css/bootstrap.min.css">
<link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/bootstrap-datepicker/1.2.0/css/datepicker.css">
<script src="//cdnjs.cloudflare.com/ajax/libs/bootstrap-datepicker/1.2.0/js/bootstrap-datepicker.js"></script>
<input id="datepicker">

JavaScript

var dateobj = new Date(); //Get today's date
var yesterday = new Date(dateobj.getFullYear(),dateobj.getMonth(),dateobj.getDay() -2);
var lastDate = new Date(dateobj.getFullYear(), dateobj.getMonth() + 1, 0);  //To get the last date of today's month

$("#datepicker").datepicker({
    startDate: yesterday,
    //endDate: lastDate
});