防抖动（Debouncing）和节流阀（Throttling）

https://jinlong.github.io/2016/04/24/Debouncing-and-Throttling-Explained-Through-Examples/

 /**
         * 函数节流
         * */
        throttle: function(handler, wait) {
            var lastTime = 0;
            return function() {
              var nowTime = new Date().getTime();
              if(nowTime - lastTime > wait) {
                  handler.apply(this, arguments);
                  lastTime = nowTime;
              } else {
                  myAlert('请勿频繁点击！');
              }
            };
        },
        /**
         * 函数防抖
         * */
        debounce: function(handler, delay) {
            var timer = null;
            return function() {
                var _self = this, _args = arguments;
                clearTimeout(timer);
                timer = setTimeout(function() {
                    handler.apply(_self, _args);
                }, delay);
            };
        }
    };