# 置頂按鈕
~~~
$(document).scroll(function () {
// 獲取滾動高度
let scrollH = $(document).scrollTop();
// 控制顯隱性
let min = 100, max = 300;
if (scrollH => min && scrollH <= max) {
$('#topping').css({opacity: (scrollH - min) / max});
}
});
function topping() {
$('html , body').animate({scrollTop: 0});
}
~~~
# 延時執行
~~~
let t;
clearTimeout(t)
t = setTimeout(function (){
console.log('執行了');
}, 1000);
~~~
