// Only load this file on forms with department and section <select>s
// that you want linked - see advanced search form as an example

var loadregions = function(data) {
  // turn the JSON into HTML
  // we should be getting an object
  var subregion_options = '<option value="">All sections</option>';
  var regions = eval(data);
  // regions should now be an array of Department subsections
  
  for (var i=0; i < regions.length; i++) {
    subregion_options += '<option value="'
        + regions[i] + '">'
        + regions[i] + '</option>';
  };
  
    // load the HTML into the section SELECT + re-enable
    $('select#selectsection').removeAttr('disabled')
                              .empty()
                              .prepend(subregion_options)
                              .find('option:first')
                              .attr('selected', 'selected');
}

// add a selectOptions function to jQuery
jQuery.fn.selectOptions = function(value) {
    this.each(
        function()  {
            if(this.nodeName.toLowerCase() != "select") return;
            
            // get number of options
            var optionsLength = this.options.length;
            
            
            for(var i = 0; i<optionsLength; i++) {
                if (this.options[i].value == value) {
                    this.options[i].selected = true;
                };
            }
        }
    )
    return this;
}

$(document).ready(
  function() {
    // preselect any previous dept/sections
    $('select#selectdept').selectOptions( $('#hiddendept').val() );
    $('select#selectsection').selectOptions( $('#hiddensection').val() );

    $('select#selectdept').change(
      function() {
        var selected_dept = $('select#selectdept').val();
          // display Loading...
          $('select#selectsection').attr('disabled','disabled')
                                     .empty()
                                     .prepend('<option value="">Loading...</option>');

          $.get(base_url + '/ajax/get_sections/'+selected_dept, null, loadregions);
      }
    );
  }
);