JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://requirejs.org/docs/release/2.1.11/minified/require.js"></script>
<input type="text" id="txtDate" value="March 2016" />

JavaScript

var date = document.getElementById("txtDate").value.split(" ");
var year = date[1];
var sMonthName = date[0]; 
var iMonthNo = new Date(sMonthName + "01, "+year).getMonth(); 
var FirstDay = new Date(year, iMonthNo, 1);
var LastDay = new Date(year, iMonthNo + 1, 0);

console.log(FirstDay);
console.log(LastDay);