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防抖debounce与节流throttle.html
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防抖debounce与节流throttle.html
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>防抖debounce 与 节流throttle</title>
</head>
<body style="padding: 100px 20% 0 0; text-align: right">
<div>原生态：<input id="noAction" /></div>
<br />
<div>防抖100ms：<input id="debounce" /></div>
<br />
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">滑动节流100ms测试</div>
<div style="height: 100px">到底</div>
<script>
let last = Date.now();
//模拟一段ajax请求
function ajax(content) {
const d = Date.now();
const span = d - last;
console.log(`${content} 间隔 ${span}ms`);
last = d;
}
const noActionInput = document.getElementById('noAction');
noActionInput.addEventListener('keyup', function(e) {
ajax(e.target.value);
});
/**
* 一般利用闭包存储和私有化定时器 `timer`
* 在 `delay` 时间内再次调用则清除未执行的定时器
* 重新定时器
* @param fn
* @param delay
* @returns {Function}
*/
function debounce(fn, delay) {
let timer = null;
return function() {
timer && clearTimeout(timer);
timer = setTimeout(() => fn.apply(this, arguments), delay);
};
}
const debounceInput = document.getElementById('debounce');
const debounceAjax = debounce(ajax, 100);
debounceInput.addEventListener('keyup', function(e) {
debounceAjax(e.target.value);
});
/**
* 时间戳来处理首次和间隔执行问题
* 定会器来确保最后一次状态改变得到执行
* @param fn
* @param delay
* @returns {Function}
*/
function throttle(fn, delay) {
let timer, lastTime;
return function() {
const now = Date.now();
const space = now - lastTime;
if( lastTime && space < delay ) {
timer && clearTimeout(timer);
timer = setTimeout(() => {
lastTime = Date.now();
console.log('setTimeout');
fn.apply(this, arguments);
}, delay - space);
return;
}
lastTime = now;
fn.apply(this, arguments);
timer && clearTimeout(timer);
};
}
const throttleAjax = throttle(ajax, 100);
window.addEventListener('scroll', function() {
const top = document.body.scrollTop || document.documentElement.scrollTop;
throttleAjax('scrollTop: ' + top);
// ajax('scrollTop: ' + top);
});
</script>
</body>
</html>