通用storage

simple-storage.js

/**
 * 本地存储
 * @author etai
 */
Ju.add("sys.simpleStorage", function(J) {
var simpleStorage = function() {
    var oStorage,
        inited = false,
        EMPTY_FUNC = function() {},
        _setItem = EMPTY_FUNC,
        _getItem = EMPTY_FUNC,
        _removeItem = EMPTY_FUNC;

    return {
        init: function() {
            var doc = document,
                ie = doc.all,
                STR_UNDEFINED = 'undefined',
                IE_STORE_NAME = 'IEDataStore'; // IE6，7下，保存数据的xml文件名

            if (inited) {return;}

            if (typeof localStorage !== STR_UNDEFINED) {
                // for IE8, FF 3.6, Chrome 4.1+, Safari 4+, Opera 10.5
                oStorage = localStorage;
            } else if (typeof globalStorage !== STR_UNDEFINED) {
                // for FF unsupport localStorage
                oStorage = globalStorage[location.hostname];
            } else if (ie) { // IE6, 7，使用userData
                oStorage = doc.createElement('input');
                oStorage.type = 'hidden';
                doc.body.appendChild(oStorage);
                oStorage.addBehavior('#default#userData');
            }

            _setItem = function(key, value) {
                var func = EMPTY_FUNC;

                if ('setItem' in oStorage) {
                    func = function(key, value) {
                        oStorage.setItem(key, value);
                    };
                } else if (ie) {
                    func = function(key, value) {
                        /*
                         * 添加try...catch的原因是：某些用户的IE，可能将安全级别设置得过高，或当前站点被添加至"受限站点"中(会
                         * 禁用掉"安全"tab下的"持续使用用户数据"选项，从而导致userData无法使用，这里通过try...catch来避免此
                         * 情况下的JS报错，下同。
                         */
                        try {
                            oStorage.setAttribute(key, value);
                            oStorage.save(IE_STORE_NAME);                       
                        } catch(e){}
                    };
                }

                return func;
            }();

            _getItem = function(key) {
                var func = EMPTY_FUNC;

                if ('getItem' in oStorage) {
                    func = function(key) {
                        return oStorage.getItem(key); 
                    };
                } else if (ie) {
                    func = function(key) {
                        try {
                            oStorage.load(IE_STORE_NAME);
                            return oStorage.getAttribute(key);                      
                        } catch(e){}
                    };
                }

                return func;
            }();

            _removeItem = function(key) {
                var func = EMPTY_FUNC;

                if ('removeItem' in oStorage) {
                    func = function(key) {
                        oStorage.removeItem(key);
                    };
                } else if (ie) {
                    func = function(key) {
                        try {
                            oStorage.removeAttribute(key);
                            oStorage.save(IE_STORE_NAME);                       
                        } catch(e){}
                    };
                }

                return func;
            }();

            inited = true;
        },

        setItem: function(key, value) {
            return _setItem(key, value);
        },

        getItem: function(key) {
            return _getItem(key);
        },

        removeItem: function(key) {
            return _removeItem(key);
        }
    };
}();

    J.sys.simpleStorage = simpleStorage;
    
})