javascript之throttle(节流)与debounce(防抖)

throttle适用于resize或者鼠标移动事件，防止浏览器频繁响应事件，严重拉低性能

function throttle(method, delay) {
  var timer = null,
    last = 0,
    ctx,
    args,
    exec = function () {
      method.apply(ctx, args);
      last = +new Date;
    };
  return function () {
    var now = +new Date,
    diff = now - last - delay;
    ctx = this;
    args = arguments;
    clearTimeout(timer);
    if (diff >= 0) {
      exec()
    } else {
      timer = setTimeout(exec, -diff)
    }
  }
}

debounce适用于诸如input事件，当用户输入时需要响应ajax请求，多次input只响应一次回调方法

function debounce(method, delay) {
  var timer = null,
  ctx,
  args;
  return function () {
    ctx = this;
    args = arguments;
    clearTimeout(timer);
    timer = setTimeout(function () {
      method.apply(ctx, args);
    }, delay);
  }
}