jquery - Unable to roll over date to 2015 -

i have script gets me date of lastmonth, current month , next month. see below

 $(document).ready(function () {    var d = new date();    var monthnames = ["january", "february", "march", "april", "may", "june", "july", "august",                "september", "october", "november", "december"];    var pastmonth = monthnames[d.getmonth() - 1].tostring();    alert('past month: ' + pastmonth);    var monthlymonth = monthnames[d.getmonth()].tostring();    alert('current month: ' + monthlymonth);    var futuremonth = monthnames[d.getmonth() + 1].tostring();    alert('future month: ' + futuremonth);    //error on here , not sure why  }); 

i think problem adding month our current month , roll on new year 2015 , breaks.

i have been reading few threads , cannot find answer this. broke entered december , has been working fine other 2014 months.

here fiddle of issue.

anybody experienced same problem , me out links threads may me?

edit: - need future month january

you have array of months , trying access var futuremonth = monthnames[d.getmonth() + 1].tostring();. here d.getmonth() + 1 13 , month has 12 elements; hence giving array out of index exception.

you can overcome problem using %12 calculating monthnames array index.

try below code :

var pastmonth = monthnames[(d.getmonth() - 1)%12].tostring();                   alert('past month: ' + pastmonth);   var monthlymonth = monthnames[(d.getmonth())%12].tostring();                   alert('current month: ' + monthlymonth);   var futuremonth = monthnames[(d.getmonth() + 1)%12].tostring();                   alert('future month: ' + futuremonth); 

demo

edit - above solution fail if current month january d.getmonth()=0, overcome problem need update below code -

var pastmonth = monthnames[(d.getmonth() > 0)?((d.getmonth() - 1)%12):11].tostring();