Question

I would like to convert a string to date object and add in the last three month from the date to form a quarterly report using javascript.

For example, I am receiving the following string “August-2010” using the following

var currDate = "August-2010";

Based on the date, I will need to compute the last three months from the current date, for example:
July-2010
June-2010
May-2010

Lastly, I will need to format that result into an array in the following format:

[May,Jun,Jul,Aug];

How should I do it in Javascript?

Answer 1

This function returns the month+year of the last X months:

function getPastXMonths(theDate, X) {

    var d = new Date(Date.parse(theDate.replace('-', ' 1 ')));
    var out = [];
    var i = 0;

    while (i++ < X) {
        out.push([
        'January','February','March','April','May','June','July','August','September','October','November','December'
        ][d.getMonth()] + '-' + d.getFullYear());
        d.setMonth(d.getMonth() - 1);
    }

    return out;
}

var months = getPastXMonths('August-2010', 3);
alert(months.join('\n'));

http://jsfiddle.net/SLcNJ/4/