/**
         * 函数节流 - 限制函数被频繁调用
         * @param  {Function} fn       [需要执行的函数]
         * @param  {[type]}   interval [限制多长的时间再重复执行fn]
         */
        var throttle = function(fn, interval) {
            var __self = fn,
                timer,
                firstTime = true;

            return function() {
                var args = arguments,
                    __me = this;

                if (firstTime) {
                    __self.apply(__me, args);
                    return firstTime = false;
                };

                if (timer) {
                    return false;
                };

                timer = setTimeout(function() {
                    clearTimeout(timer);
                    timer = null;
                    __self.apply(__me, args);
                }, interval || 500);
            };
        };

        // test
        function A() {
            console.log(‘A‘);
        };
        var A2 = throttle(A, 1000);

        setInterval(A2, 100);