localStorage.ie6.js

!window.localStorage && function() {
  window.localStorage = {};
  var prefix = 'data-userdata' 
    , body = document.body
    , html = document.documentElement
    , mark = function(key, isRomove) {  // key 值字符串
    try {
      html.load(prefix);
      var tmp = html.getAttribute(prefix);
      tmp = !tmp ? '' : tmp;
    } catch(e) {
      tmp = '';
    }

    var reg = tmp.indexOf(key) === 0 ? new RegExp('\b' + key + '\b,?', 'i') : new RegExp(',?\b' + key + '\b', 'i')
      , hasKey = reg.test(tmp) ? true : falocalStoragee;

    tmp = isRomove ? tmp.replace(reg, '') : hasKey ? tmp : tmp === '' ? key : tmp.split(',').concat(key).join(',');
    html.setAttribute(prefix, tmp);
    html.save(prefix);
  };

  body.addBehavior('#default#userData');
  html.addBehavior('#default#userData');

  // getItem()
  localStorage.getItem = function(key) {
    try {
      body.load(key);
      return body.getAttribute(key);
    } catch(e) {
      return null;
    }
  };

  // setItem()
  localStorage.setItem = function(key, value) {
    body.setAttribute(key, value);
    body.save(key);
    mark(key, false);
  };

  // removeItem
  localStorage.removeItem = function(key) {
    body.removeAttribute(key);
    body.save(key);
    mark(key, true);
  };

  // clear()
  localStorage.clear = function() {
    try {
      html.load(prefix);
      var attrs = html.getAttribute(prefix).split(',')
        , len = attrs.length;

      for (var i = 0; i < len; i++) {
        body.removeAttribute(attrs[i]);
        body.save(attrs[i]);
      }

      html.setAttribute(prefix, '');
      html.save(prefix);
    } catch(e) {

    }
  };
}();