<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>防抖函数第二遍</title>
</head>
<body>
<div id="main" style="width: 100%; height: 300px; border: 1px solid red"></div>
<button id="btn">点击阻止</button>
<script>
const main = document.getElementById('main');
const btn = document.getElementById('btn');
let count = 0;
function doSomething(e) {
console.log(e);
console.log(this);
count++;
main.innerText = count;
}
main.onmousemove = debounce(doSomething, 1000, true);
function debounce(func, delay, immediate) {
let timer, result;
let debounced = function () {
let context = this;
let args = arguments;
clearTimeout(timer);
if (immediate) {
let callNow = !timer;
timer = setTimeout(function () {
timer = null;
}, delay);
if (callNow) result = func.apply(context, args);
} else {
timer = setTimeout(function () {
func.apply(context, args);
}, delay);
}
return result;
};
return debounced;
}
let concept = `事件处理函数需要延迟一段时间后执行，如果在这段时间，该函数再次被调用，则重新计算延迟时间，若延迟时间内没有再次调用，则执行函数相应逻辑`;
let environment = `scroll滚动事件；搜索框输入查询；表单验证；按钮提交；监听窗口变化 onresize 事件`;
</script>
</body>
</html>
