<!DOCTYPE html><html>    <head>        <meta charset="utf-8">        <title>防抖和节流</title>    </head>    <body>        <input type="" name="" id="input" value="" />        <script>            const debounce = function(fn, delay = 300) {                let timer = null                return function() {                    if (timer) clearTimeout(timer)                    timer = setTimeout(() => {                        fn.apply(null, arguments)                        timer = null                    }, delay)                }            }                        const throttle = function(fn, delay = 300) {                let timer = null                return function() {                    if (timer) return                    timer = setTimeout(() => {                        fn.apply(null, arguments)                        timer = null                    }, delay)                }            }            // 防抖测试            const input = document.getElementById('input')            input.addEventListener('input', debounce((ev) => {                console.log(ev.target.value)            }, 500))            // 节流测试            window.addEventListener('resize', throttle((ev) => {                console.log('resize', ev)            }, 500))        </script>    </body></html>