跨浏览器的 mouseenter mouseleave 以及 compareDocumentP(2)

// flag 类
    function flag(sFlags) {
        this._flags = {};
        this._status = 0;
        sFlags && this.initFlags(sFlags);
    }
    flag.prototype = {
        constructor: flag,
        initFlags: function(sFlags) {//sFlags "状态1,状态2,状态3...... 初始化原始标识集合...
            sFlags = sFlags.split(',');
            for (var i = 0, len = sFlags.length; i < len; i++) this._flags[sFlags[i]] = 1 << i;

           //这里初始化标识的值 如果同时具备n种状态 则 每种状态的值一定是 000001  000010 000100 001000 010000 100000 
        },
        setStatus: function(sFlags) { //sFlags "状态1,状态3......设置当前状态
            sFlags = sFlags.split(',');

　　　　this._status=0;
            for (var i = 0, len = sFlags.length; i < len; i++) {
                this._check[sFlags[i]];
                this._status |= this._flags[sFlags[i]];
            }
        },
        addStatus: function(sFlags) {//sFlags "状态1,状态3......检查当前状态标示 是否有 状态1和状态3 如果没有则添加
            sFlags = sFlags.split(',');
            for (var i = 0, len = sFlags.length; i < len; i++) {
                this._check(sFlags[i]);
                if (this.hasStatus(sFlags[i])) continue; //判断是否已经有这个状态如果有 跳过.
               this._status |= this._flags[sFlags[i]];

                //当前的状态值 与 允许的标识值 做 | 运算 即添加状态
            }
        },
        removeStatus: function(sFlags) {
            sFlags = sFlags.split(',');
            for (var i = 0, len = sFlags.length; i < len; i++) {
                this._check(sFlags[i]);
                if (!this.hasStatus(sFlags[i])) continue;
               this._status ^= this._flags[sFlags[i]];

                // 当前状态值 与 要去掉的状态值做 ^运算 即删除状态
            }
        },
        clear: function() {
            this._status = 0;
        },
        hasStatus: function(sFlags) {//sFlags "状态1,状态3.....状态 n.检查当前状态标识 是否同时 具备状态1和状态3 以及状态n
            sFlags = sFlags.split(',');
            for (var i = 0, len = sFlags.length; i < len; i++) {
                this._check(sFlags[i]);
                if ((this._status & this._flags[sFlags[i]]) != this._flags[sFlags[i]]) return false;