useeffect

nested or loop statements. Function examplewithmanystates () {// Method for declaring various states and updating corresponding states if (math. random () gt; 1) {const [age, setage] = usestate (42); const [Todos, settodos] = usestate ([{text: 'Learn hooks'}]);} else {const [fruit, setfruit] = usestate ('bana'); const [Todos, settodos] = usestate ([{text: 'Learn hooks'}]);} //...} ?? The preceding method is not allowed because a function component can have multiple state hooks and usestate ret

look at the usage of Hoos. Here we will talk about the two most important hooks: usestate and useeffect. Let's first look at an example that you may have seen many times. import { useState, useEffect } from 'react';function Example() { const [count, setCount] = useState(0); useEffect(() =gt; { document.title = `You clicked ${count} times`; }); return (

Reprint please indicate the source: http://blog.csdn.net/lmj623565791/article/details/44098729, this article from: "Zhang Hongyang Blog" 1, overviewThe creation of this blog, is because, the group of friends to send me a warm, and then asked me how to achieve the top of the Viewpager indicator font discoloration, this is:Probably the app of the headlines today, the magical place is that when switching Viewpager page, the top indicator changed to the font color changes, personally feel good.So th

How to use1. Refer to jquery and jquery.lazyload.js to your page="Jquery-1.11.0.min.js" >/script>="Jquery.lazyload.js?v =1.9.1 ">/script>2. Add style for picture lazy picture Path reference method with Data-originalClass="lazy" data-original="Img/bmw_m1_hood.jpg" >class=" Lazy "Data-original=" Img/bmw_m1_side.jpg ">3, JS out of the lazyload and set the image display mode="Text/javascript" charset= "utf-8" > $ (function () {$ ("Img.lazy"). LazyLoad ({effect: "fadeIn"}); });/script> You can

/grey.gif",Pre-occupied with picturesplaceholder, the value is a path to a picture. This image is used to occupy the location of the image to be loaded, and when the image is loaded, the bitmap will be hidden//effect:"FadeIn",What effect is loaded in useeffect (special effects), values have show (direct display), FadeIn (Fade in), Slidedown (dropdown), etc., commonly used fadeIn//threshold:200, //start loading //threshold in advance, values are number