change calender date?

[italodance]

hey guys i am persian and today is 24 in my calender date here

please guide me how can i change this calender date in my lockscreen theme?

var this_date_timestamp = new Date()    

  var this_weekday = this_date_timestamp.getDay()    
  var this_date = this_date_timestamp.getDate()    
  var this_month = this_date_timestamp.getMonth()

well we know "var this_date_timestamp = new Date()" is the default calender date
but today is another date here

how can i fix it for my lockscreen theme? and what should put for this " = new Date"?


tnx