var num = 1;
var content = document.getElementById('content');
var lastDate = new Date().getTime();

// 鼠标移动事件
function count1() {
  content.innerHTML = '鼠标移动事件' + num++;

  var nowDate = new Date().getTime();
  // 输出两次相隔执行时间差
  console.log(nowDate-lastDate)
  lastDate = nowDate
};
content.onmousemove = throttle(count1, 0);


// 页面滚动事件
function count2() {
  content.innerHTML = '面滚动事件' + num++;

  var nowDate = new Date().getTime();
  // 输出两次相隔执行时间差
  console.log(nowDate-lastDate)
  lastDate = nowDate
};

window.onscroll = throttle(count2, 0);

/**
 * @desc 函数节流-合成版
 * @param func 函数
 * @param wait 延迟执行毫秒数
 * @param immediate true - 立即执行（时间戳版）， false - 延迟执行（定时器版）
 */
function throttle(func, wait, immediate) {
  if (immediate) {
    var previous = 0;
  } else {
    var timer;
  }
  return function() {
    var context = this;
    var args = arguments;
    if (immediate) {
      var now = Date.now();

      if (now - previous > wait) {
        func.apply(context, args);
        previous = now;
      }
    } else {
      if (!timer) {
        timer = setTimeout(() => {
          timer = null;
          func.apply(context, args)
        }, wait)
      }
    }
  }
}