A gist providing the code for handling and saving the statuses of checkboxes using localStorage.

optionsPage.js

$(function(){

  // Get settings from local storage
  var settings_pronounceable = localStorage.getItem("settings_pronounceable") == "true";
  var settings_capitals      = localStorage.getItem("settings_capitals") == "true";
  var settings_numbers       = localStorage.getItem("settings_numbers") == "true";
  var settings_symbols       = localStorage.getItem("settings_symbols") == "true";

  // Configure settings display with values from local storage, or use defaults
  $("#settings_pronounceable").prop("checked", settings_pronounceable);
  $("#settings_capitals").prop("checked", settings_capitals);
  $("#settings_numbers").prop("checked", settings_numbers);
  $("#settings_symbols").prop("checked", settings_symbols);

  // Handle changes of settings
  $("#settings_pronounceable").change(function() {
    pronounceable = $(this).prop("checked"); 
    localStorage.setItem("settings_pronounceable", pronounceable);
  });

  $("#settings_capitals").change(function() {
    capitals = $(this).prop("checked"); 
    localStorage.setItem("settings_capitals", capitals);
  });

  $("#settings_numbers").change(function() {
    numbers = $(this).prop("checked"); 
    localStorage.setItem("settings_numbers", numbers);
  });

  $("#settings_symbols").change(function() {
    symbols = $(this).prop("checked"); 
    localStorage.setItem("settings_symbols", symbols);
  });
});