Script used to link two selects acording to some options

jquery.select_linker.js

/*
  Select Linker: This extension links two selects so the options loaded depends on each select.

  How to use it:

    > options = {"__default" : ...}
    > $("#select_one").link_select("#select_two", options, false);

  Params: 
    * other_select : Selector to reach other select
    * options: a hash of options with the following format
      { "value of this select" : { "values": 
        [
          { "label" : "Label for the option 1", "value" : "Value for the option 1" },
          { "label" : "Label for the option 2", "value" : "Value for the option 2" },
          ...
        ],
        ...
        ,"__default" : { "values": 
        [
          { "label" : "Label for the option 1", "value" : "Value for the option 1" },
          { "label" : "Label for the option 2", "value" : "Value for the option 2" },
          ...
        ]
      }


      "__default" key set the default options for the linked select

    * mutual: If the relationship is mutual we must change the behaviour a little bit. 
      NOTE: Working with mutual links is a little bit weird (and nasty right now). 
      We must call the function on both selects, passing the apropiate options for each functions.

      I mean it's not as simple as:

        > options = {"__default" : ...}
        > $("#select_one").link_select("#select_two", options, true);

      But

        > options_1 = {"__default" : ...}
        > options_2 = {"__default" : ...} // Not are different hashes
        > $("#select_one").link_select("#select_two", options_1, true);
        > $("#select_two").link_select("#select_one", options_2, true);

*/
$.fn.link_select = function(other_select, options, mutual)
{

  $(this).change(function(e) {
    if (mutual && $(other_select).hasClass("main_selector"))
    {
      return false;
    }
    $(other_select).empty();
    option = options[$(this).val()]
    if (!option)
    {
      option = options["__default"]
    }  
    selected = true;
    for (value in option["values"])
    {
      value = option["values"][value]
      $(other_select).append("<option value='"+value.value+"' "+(selected ? "selected=selected" : "")+">"+value.label+"</option>")
      selected = false;
    }
    $(other_select).parent().children("span").text(option["values"][0].label);

    if (mutual)
    {
      if ($(this).val().value == "")
      {
        $(this).removeClass("main_selector");
      }
      else
      {
        $(this).addClass("main_selector");  
      }
      
    }

  });
};