Javascript 根据一天中的时间更新背景图像而无需刷新页面的最佳实践
所以我刚刚做了Brad Traversy的动态登录页教程。这是一个很好的教程,但我希望实现同样的效果,而不必刷新页面,以便在小时数<12、<16或以下代码中指定的其他时间看到背景图像的变化。更重要的是,我想知道实现这一目标的最佳或最合适的做法,而不是以任何可能的方式去做 如果需要进一步澄清我的问题,请询问 多谢各位Javascript 根据一天中的时间更新背景图像而无需刷新页面的最佳实践,javascript,css,ajax,dynamically-generated,page-refresh,Javascript,Css,Ajax,Dynamically Generated,Page Refresh,所以我刚刚做了Brad Traversy的动态登录页教程。这是一个很好的教程,但我希望实现同样的效果,而不必刷新页面,以便在小时数
HTML
<time id="time"></time>
<h1>
<span id="greeting"></span>
<span id="name" contenteditable="true"></span>
</h1>
<h2>What Is Your Focus For Today?</h2>
<h2 id="focus" contenteditable="true"></h2>
JS
// DOM Elements
const time = document.getElementById('time'),
greeting = document.getElementById('greeting'),
name = document.getElementById('name'),
focus = document.getElementById('focus');
// Options
const showAmPm = true;
// Show Time
function showTime() {
let today = new Date(),
hour = today.getHours(),
min = today.getMinutes(),
sec = today.getSeconds();
// Set AM or PM
const amPm = hour >= 12 ? 'PM' : 'AM';
// 12hr Format
hour = hour % 12 || 12;
// Output Time
time.innerHTML = `${hour}<span>:</span>${addZero(min)}<span>:</span>${addZero(
sec
)} ${showAmPm ? amPm : ''}`;
setTimeout(showTime, 1000);
}
// Add Zeros
function addZero(n) {
return (parseInt(n, 10) < 10 ? '0' : '') + n;
}
// Set Background and Greeting
function setBgGreet() {
let today = new Date(),
hour = today.getHours();
if (hour < 12) {
// Morning
document.body.style.backgroundImage = "url('https://i.ibb.co/7vDLJFb/morning.jpg')";
greeting.textContent = 'Good Morning, ';
} else if (hour < 18) {
// Afternoon
document.body.style.backgroundImage = "url('https://i.ibb.co/3mThcXc/afternoon.jpg')";
greeting.textContent = 'Good Afternoon, ';
} else {
// Evening
document.body.style.backgroundImage = "url('https://i.ibb.co/924T2Wv/night.jpg')";
greeting.textContent = 'Good Evening, ';
document.body.style.color = 'white';
}
}
// Get Name
function getName() {
if (localStorage.getItem('name') === null) {
name.textContent = '[Enter Name]';
} else {
name.textContent = localStorage.getItem('name');
}
}
// Set Name
function setName(e) {
if (e.type === 'keypress') {
// Make sure enter is pressed
if (e.which == 13 || e.keyCode == 13) {
localStorage.setItem('name', e.target.innerText);
name.blur();
}
} else {
localStorage.setItem('name', e.target.innerText);
}
}
// Get Focus
function getFocus() {
if (localStorage.getItem('focus') === null) {
focus.textContent = '[Enter Focus]';
} else {
focus.textContent = localStorage.getItem('focus');
}
}
// Set Focus
function setFocus(e) {
if (e.type === 'keypress') {
// Make sure enter is pressed
if (e.which == 13 || e.keyCode == 13) {
localStorage.setItem('focus', e.target.innerText);
focus.blur();
}
} else {
localStorage.setItem('focus', e.target.innerText);
}
}
name.addEventListener('keypress', setName);
name.addEventListener('blur', setName);
focus.addEventListener('keypress', setFocus);
focus.addEventListener('blur', setFocus);
// Run
showTime();
setBgGreet();
getName();
getFocus();
CSS
* {
box-sizing: border-box;
margin: 0;
padding: 0;
}
body {
font-family: 'Quicksand', sans-serif;
display: flex;
flex-direction: column;
align-items: center;
justify-content: center;
text-align: center;
height: 100vh;
color: black;
}
#time {
font-size: 8rem;
}
h1 {
margin-bottom: 3rem;
}
h2 {
margin-bottom: 0.5rem;
opacity: 0.6;
}
@media (max-width: 700px) {
#time {
font-size: 6rem;
}
}
HTML
你今天的重点是什么?
JS
//DOM元素
const time=document.getElementById('time'),
greeting=document.getElementById('greeting'),
name=document.getElementById('name'),
focus=document.getElementById('focus');
//选择权
const showAmPm=真;
//表演时间
函数showTime(){
让今天=新日期(),
小时=今天。getHours(),
min=today.getMinutes(),
sec=today.getSeconds();
//设定上午或下午
常数amPm=hour>=12?'PM':'AM';
//12小时格式
小时=小时%12 | | 12;
//输出时间
time.innerHTML=`${hour}:${addZero(min)}:${addZero(
秒
)}${showAmPm?amPm:'}`;
设置超时(显示时间,1000);
}
//加零
函数addZero(n){
返回(parseInt(n,10)<10?'0':'')+n;
}
//设置背景和问候语
函数setbgreet(){
让今天=新日期(),
小时=今天。getHours();
如果(小时<12){
//早晨
document.body.style.backgroundImage=“url('https://i.ibb.co/7vDLJFb/morning.jpg')";
greeting.textContent='早上好';
}否则,如果(小时<18){
//下午
document.body.style.backgroundImage=“url('https://i.ibb.co/3mThcXc/afternoon.jpg')";
greeting.textContent='下午好';
}否则{
//晚上
document.body.style.backgroundImage=“url('https://i.ibb.co/924T2Wv/night.jpg')";
greeting.textContent='晚上好';
document.body.style.color='white';
}
}
//得名
函数getName(){
if(localStorage.getItem('name')==null){
name.textContent='[输入名称]';
}否则{
name.textContent=localStorage.getItem('name');
}
}
//设置名称
函数集合名(e){
如果(e.type==='keypress'){
//确保已按enter键
if(e.which==13 | | e.keyCode==13){
localStorage.setItem('name',e.target.innerText);
name.blur();
}
}否则{
localStorage.setItem('name',e.target.innerText);
}
}
//集中注意力
函数getFocus(){
if(localStorage.getItem('focus')==null){
focus.textContent='[输入焦点]';
}否则{
focus.textContent=localStorage.getItem('focus');
}
}
//聚焦
函数设置焦点(e){
如果(e.type==='keypress'){
//确保已按enter键
if(e.which==13 | | e.keyCode==13){
setItem('focus',e.target.innerText);
focus.blur();
}
}否则{
setItem('focus',e.target.innerText);
}
}
name.addEventListener('keypress',setName);
name.addEventListener('blur',setName);
focus.addEventListener('keypress',setFocus);
focus.addEventListener('blur',setFocus);
//跑
showTime();
sebbgreet();
getName();
getFocus();
CSS
* {
框大小:边框框;
保证金:0;
填充:0;
}
身体{
字体系列:“流沙”,无衬线;
显示器:flex;
弯曲方向:立柱;
对齐项目:居中;
证明内容:中心;
文本对齐:居中;
高度:100vh;
颜色:黑色;
}
#时间{
字号:8rem;
}
h1{
边缘底部:3rem;
}
氢{
边缘底部:0.5雷姆;
不透明度:0.6;
}
@介质(最大宽度:700px){
#时间{
字号:6rem;
}
}
以下是一个仅修改setBgGreet
功能的解决方案:
// Set Background and Greeting
function setBgGreet() {
let today = new Date(),
hour = today.getHours();
const now = today.getTime(); // this is the current time represented in milliseconds
let nextChange; // this variable will tell when the next change of bg should occur
if (hour < 12) {
// Morning
document.body.style.backgroundImage = "url('https://i.ibb.co/7vDLJFb/morning.jpg')";
greeting.textContent = 'Good Morning, ';
nextChange = today.setHours(12, 0, 0, 0); // Next change will be at 12 today
} else if (hour < 18) {
// Afternoon
document.body.style.backgroundImage = "url('https://i.ibb.co/3mThcXc/afternoon.jpg')";
greeting.textContent = 'Good Afternoon, ';
nextChange = today.setHours(18, 0, 0, 0); // Next change will be at 18 today
} else {
// Evening
document.body.style.backgroundImage = "url('https://i.ibb.co/924T2Wv/night.jpg')";
greeting.textContent = 'Good Evening, ';
document.body.style.color = 'white';
nextChange = today.setHours(24, 0, 0, 0); // Next change will be at midnight, going to tomorrow
}
setTimeout(setBgGreet, nextChange - now); // This timeout will wait the correct amount of time
// and then will trigger this very same function again
}
//设置背景和问候语
函数setbgreet(){
让今天=新日期(),
小时=今天。getHours();
const now=today.getTime();//这是以毫秒表示的当前时间
let nextChange;//此变量将告诉下一次更改bg的时间
如果(小时<12){
//早晨
document.body.style.backgroundImage=“url('https://i.ibb.co/7vDLJFb/morning.jpg')";
greeting.textContent='早上好';
nextChange=today.setHours(12,0,0,0);//下一次更改将在今天12点进行
}否则,如果(小时<18){
//下午
document.body.style.backgroundImage=“url('https://i.ibb.co/3mThcXc/afternoon.jpg')";
greeting.textContent='下午好';
nextChange=today.setHours(18,0,0,0);//下一次更改将在今天18点进行
}否则{
//晚上
document.body.style.backgroundImage=“url('https://i.ibb.co/924T2Wv/night.jpg')";
greeting.textContent='晚上好';
document.body.style.color='white';
nextChange=today.setHours(24,0,0,0);//下一次更改将在午夜进行,直到明天
}
setTimeout(setBgGreet,nextChange-now);//此超时将等待正确的时间量
//然后会再次触发这个相同的函数
}
如果此代码有效,您应该查看,看看您的问题是否与主题相关。事实上,“最佳实践”问题在这里几乎总是离题,因为它们需要征求意见。非常感谢。我感谢你的建议。