scinote-web/app/assets/javascripts/samples/samples_importer.js

var previousIndex;
var disabledOptions;
$("select").focus(function() {
  previousIndex = $(this)[0].selectedIndex;
}).change(function () {
  var currSelect = $(this);
  var currIndex = $(currSelect)[0].selectedIndex;

  $("select").each(function() {
    if (currSelect !== $(this) && currIndex > 0) {
      $(this).children().eq(currIndex).attr("disabled", "disabled");
    }

    $(this).children().eq(previousIndex).removeAttr("disabled");
  });

  previousIndex = currIndex;
});

//  Create import samples ajax
$("form#form-import")
.submit(function(e) {
  disabledOptions = $("option[disabled='disabled']");
  disabledOptions.removeAttr("disabled");
})
.on("ajax:success", function(ev, data, status) {
  // Simply reload page to show flash and updated samples list
  location.reload();
})
.on("ajax:error", function(ev, data, status) {
  if (_.isUndefined(data.responseJSON.html)) {
    // Simply reload page to show flash
     location.reload();
  } else {
    // Re-disable options
    disabledOptions.attr("disabled", "disabled");

    // Populate the errors container
    $("#import-errors-container").html(data.responseJSON.html);
  }
});