Not submitting state or province from other picklists

Not submitting state or province from other picklists

I have a form that displays a select box for state or province (HTML name="state") depending upon what country is selected. For example, when United States is selected from the 'Country' select box, all the US states appear in another select box called 'States'. When Canada is selected from the 'Country' select box, all Canadian provinces appear in another select box. This is also the case for several other countries. 

The issue is this, when submitting, say United States and Colorado, the submission data displays the 'CO' for Colorado, plus commas, which are coming from the other "state" fields, such as the following:

CO,,,,,,

How can I configure it so that the commas aren't submitted, which a generated from the blanks for the other countries? 

Here's my jQuery:
  1. $(document).ready(function() {
  2.   $("#country").change(function(){
  3.     $(".geo").hide();
  4.       $("." + this.value).toggle(['AU','CA','DE','MX','US'].indexOf(this.value)!=-1);
  5.       $(".any").toggle(['AU','CA','DE','MX','US'].indexOf(this.value)==-1);
  6.   });
  7. });
All select fields include the following as the first option, which is generating the blank form submission and the comma.
  1. <option value="" selected>-- Please Select --</option>