RailsAPIDates.js

function dateFromRailsAPI(aString){
    if (!aString)
        return;
    
    var regexp = /(\d\d\d\d)(-)?(\d\d)(-)?(\d\d)(T)?(\d\d)(:)?(\d\d)(:)?(\d\d)(\.\d+)?(Z|([+-])(\d\d)(:)?(\d\d))/,
        matches = aString.match(new RegExp(regexp)),
        offset = 0,
        date = new Date();
    
    if (matches)
    {
        var d = matches;
        date.setUTCDate(1);
        date.setUTCFullYear(parseInt(d[1],10));
        date.setUTCMonth(parseInt(d[3],10) - 1);
        date.setUTCDate(parseInt(d[5],10));
        date.setUTCHours(parseInt(d[7],10));
        date.setUTCMinutes(parseInt(d[9],10));
        date.setUTCSeconds(parseInt(d[11],10));
        
        if (d[12])
            date.setUTCMilliseconds(parseFloat(d[12]) * 1000);
        else
            date.setUTCMilliseconds(0);
        
        if (d[13] != 'Z')
        {
            offset = (d[15] * 60) + parseInt(d[17],10);
            offset *= ((d[14] == '-') ? -1 : 1);
            date.setTime(date.getTime() - offset * 60 * 1000);
        }
    }
    else
        date.setTime(Date.parse(aString));
    
    return date;
}