Ndtyjky

I got an Kendo ui Chart like this one and have to show the last 12 months of todays date on the axis.

I found this to extend the date object to get the previous month. The problem seems to be when I got an Date like "2013/05/31" and the previous months got no 31st day.

Date.prototype.toPrevMonth = function (num) {

    var thisMonth = this.getMonth();

    this.setMonth(thisMonth-1);

    if(this.getMonth() != thisMonth-1 && (this.getMonth() != 11 || (thisMonth == 11 &&      this.getDate() == 1)))

    this.setDate(0);

}





new Date().toPrevMonth(11),

new Date().toPrevMonth(10),

new Date().toPrevMonth(9),

new Date().toPrevMonth(8),

new Date().toPrevMonth(7),

new Date().toPrevMonth(6),

new Date().toPrevMonth(5),

new Date().toPrevMonth(4),

new Date().toPrevMonth(3),

new Date().toPrevMonth(2),

new Date().toPrevMonth(1),

new Date().toPrevMonth(0)

Can anyone help me out with the if state?
The function is build to show only the previous month, but I need the last 12 previous months.

Or is there a much easier solution? :-)

Thanks for all!

Use Datejs (http://www.datejs.com/)

It has a built in function to add months:

Date.today().addMonths(-6);

UPDATE:
Since you're not able to include external files, here are the relevant methods from within Datejs.

/*

 * Copyright (c) 2006-2007, Coolite Inc. (http://www.coolite.com/). All rights reserved.

 * License: Licensed under The MIT License. See license.txt and http://www.datejs.com/license/. 

 * Website: http://www.datejs.com/ or http://www.coolite.com/datejs/

*/



Date.isLeapYear = function (year) {

    return (((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0));

};



Date.prototype.isLeapYear = function () {

    var y = this.getFullYear();

    return (((y % 4 === 0) && (y % 100 !== 0)) || (y % 400 === 0));

};



Date.getDaysInMonth = function (year, month) {

    return [31, (Date.isLeapYear(year) ? 29 : 28), 31, 30, 31, 30, 31, 31, 30, 31, 30, 31][month];

};



Date.prototype.getDaysInMonth = function () {

    return Date.getDaysInMonth(this.getFullYear(), this.getMonth());

};



Date.prototype.addMonths = function (value) {

    var n = this.getDate();

    this.setDate(1);

    this.setMonth(this.getMonth() + value);

    this.setDate(Math.min(n, this.getDaysInMonth()));

    return this;

};

I also needed a list of the last 12 months this is what I did:

var theMonths = new Array("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December");

var today = new Date();

var aMonth = today.getMonth();

var i;

for (i=0; i<12; i++) {

    document.writeln(theMonths[aMonth] + '<br>'); //here you can do whatever you want...

    aMonth++;

    if (aMonth > 11) {

        aMonth = 0;

    }

}

Including year of month

var monthName = new Array("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December");

var d = new Date();

for (i=0; i<=12; i++) {

    console.log(monthName[d.getMonth()] + ' ' + d.getFullYear());

    d.setMonth(d.getMonth() - 1);

}