Generates monthly time duration to execute some query, helpful when generating monthly reports.

monthly-report-time-duration.js

function getCurrentYear(){
  return (new Date()).getYear()+1900;
}
function isLeapYear(year) {
  var d = new Date(year, 1, 29);
  return d.getMonth() == 1;
}
function getMonthDays(month,year){
	var monthDays=[31,28,31,30,31,30,31,31,30,31,30,31];
	month=month%12;
	if(month==1 && isLeapYear(year)){
			return 29;
	}
	return monthDays[month];
}
function getDurationCalendar(year){
	var durationCal=[],
	monthName=["January","February","March","April","May","June","July","August","September","October","November","December"];
	for(var i=0;i<12;i++){
		durationCal[durationCal.length]={
			'start':new Date(year,i,1,0,0,0,0),
			'end':new Date(year,i,getMonthDays(i,year),23,59,59,999),
			'month':monthName[i],
		}
	}
	return durationCal;
}
function getCurrentYearDurationCalendar(){
	return getDurationCalendar(getCurrentYear());
}
function testDurationCalendar(){
	for(var year=1999;year<2013;year++){
		var durationCal=getDurationCalendar(year)
		for(var i=0;i<durationCal.length;i++){
			console.log(year,'within-->',Math.round((durationCal[i].end - durationCal[i].start)/86400000));
			if(i>0){
				console.log('transition-->',Math.round((durationCal[i].start - durationCal[i-1].end)/86400000));	
			}
			
		}
	}
}