xinxin?

JavaScript：防抖与节流

①防抖：

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <title></title>
    <style type="text/css">
        div {
            height: 2200px;
            background-color: pink;
        }
    </style>
</head>

<body>
    <div>我是内容部分</div>
    <script type="text/javascript">
        //防抖：函数只执行最后一次，若时间间隔小于500毫秒，则函数不执行
        window.onscroll = debounce(function () {
            console.log("调用了1次");
        }, 500)

        function debounce(func, delay = 300) {
            var timer
            return function () {
                var that=this
                var args=arguments
                clearTimeout(timer)
                timer = setTimeout(function(){
                    func.apply(that,args) //改变定时器中的this指向
                },delay)
            }
        }
    </script>
</body>

</html>

②节流：

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <button>点击</button>
  <script>
    //节流：函数在一定的时间里只能执行那么几次，点击后等500毫秒触发，只能500毫秒触发一次
    var btn = document.getElementsByTagName('button')[0]
    btn.onclick = throttle(function () {
      console.log(111);
    }, 500)

    function throttle(func, wait) {
      var timer
      return function () {
        var that = this
        var args = arguments
        if (!timer) {
          timer = setTimeout(function () {
            timer = null
            func.apply(that, args) //改变定时器中的this指向
          }, wait)
        }
      }
    }
  </script>
</body>

</html>

 

posted on 2020-07-25 15:06  xinxin?  阅读(107)  评论(0)    收藏  举报

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