get start and end of each month by month number javascript code example

Example 1: javascript get current month start and end date

var date = new Date();
var firstDay = new Date(date.getFullYear(), date.getMonth(), 1);
var lastDay = new Date(date.getFullYear(), date.getMonth() + 1, 0);

Example 2: how to get the number of days in a month in javascript

// instantiate a date object
 var dt = new Date();

// dt.getMonth() will return a month between 0 - 11
// we add one to get to the last day of the month 
// so that when getDate() is called it will return the last day of the month
 var month = dt.getMonth() + 1;
 var year = dt.getFullYear();

// this line does the magic (in collab with the lines above)
 var daysInMonth = new Date(year, month, 0).getDate();