saving checkbox state on reload

Purely in JavaScript supporting localStorage if available, otherwise using document.cookie.

function getStorage(key_prefix) {
    // this function will return us an object with a "set" and "get" method
    // using either localStorage if available, or defaulting to document.cookie
    if (window.localStorage) {
      // use localStorage:
      return {
        set: function(id, data) {
          localStorage.setItem(key_prefix+id, data);
        },
        get: function(id) {
          return localStorage.getItem(key_prefix+id);
        }
      };
    } else {
      // use document.cookie:
      return {
         set: function(id, data) {
           document.cookie = key_prefix+id+'='+encodeURIComponent(data);
         },
         get: function(id, data) {
           var cookies = document.cookie, parsed = {};
           cookies.replace(/([^=]+)=([^;]*);?\s*/g, function(whole, key, value) {
              parsed[key] = decodeURIComponent(value);
           });
           return parsed[key_prefix+id];
         }
       };
     }
  }

jQuery(function($) {
  // a key prefix is used for the cookie/storage
  var storedData = getStorage('com_mysite_checkboxes_'); 

  $('div.check input:checkbox').bind('change',function(){
    $('#'+this.id+'txt').toggle($(this).is(':checked'));
    // save the data on change
    storedData.set(this.id, $(this).is(':checked')?'checked':'not');
  }).each(function() {
    // on load, set the value to what we read from storage:
    var val = storedData.get(this.id);
    if (val == 'checked') $(this).attr('checked', 'checked');
    if (val == 'not') $(this).removeAttr('checked');
    if (val) $(this).trigger('change');
  });

});

jsFiddle demo available — Click some checkboxes, then “Run” the script again!