5个前端练手项目(html css js canvas)

 前言：

首先祝大家端午节快乐。本篇文章有5个练手项目
对于刚学完前端三剑客的你们。应该是一个很好的实践

目录

數.跑马灯

1.1效果图：

1.2思路解析

1.3源码

.彩虹爱心

2.1效果图

2.2思路解析

2.3源码

.闹钟

3.1效果图

3.2思路解析

3.3源码

.自制笔记本

4.1效果展示

4.2思路解析

4.3源码

.自定义写字台（也可自定义字的样式）

5.1效果展示

 5.2思路解析

5.3源码

1.跑马灯

1.1效果图：

---

1.2思路解析

在这个项目中，在html中创立20个span标签

每个span标签设置style为--i:数字的样式用于

在css中动态分配圆圈分几份，transform: rotate(calc(18deg*var(--i)))

利用filter属性结合关键帧动态切换颜色。同时设置每一个span标签进行

旋转

---

1.3源码

	
	
    
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	


    
loading

---

2.彩虹爱心

---

2.1效果图

2.2思路解析

搭建基本的html结构，采用的svg技术，

通过js动态改变颜色，以及动态实现切换图形

---

2.3源码

const colors = ["#e03776","#8f3e98","#4687bf","#3bab6f","#f9c25e","#f47274"];
const SVG_NS = 'http://www.w3.org/2000/svg';
const SVG_XLINK = "http://www.w3.org/1999/xlink";

let heartsRy = []

function useTheHeart(n){
  let use = document.createElementNS(SVG_NS, 'use');
  use.n = n;
  use.setAttributeNS(SVG_XLINK, 'xlink:href', '#heart');
  use.setAttributeNS(null, 'transform', `scale(${use.n})`);
  use.setAttributeNS(null, 'fill', colors[n%colors.length]);
  use.setAttributeNS(null, 'x', -69);
  use.setAttributeNS(null, 'y', -69);
  use.setAttributeNS(null, 'width', 138);
  use.setAttributeNS(null, 'height', 138);
  
  heartsRy.push(use)
  hearts.appendChild(use);
}

for(let n = 18; n >= 0; n--){useTheHeart(n)}

function Frame(){
  window.requestAnimationFrame(Frame);
  for(let i = 0; i < heartsRy.length; i++){
    if(heartsRy[i].n < 18){heartsRy[i].n +=.01
     }else{
     heartsRy[i].n = 0;
     hearts.appendChild(heartsRy[i])
    }
    heartsRy[i].setAttributeNS(null, 'transform', `scale(${heartsRy[i].n})`);
  }
}

Frame()

---

3.闹钟

---

3.1效果图

3.2思路解析

搭建基本的html结构，动态得到实时的时，分，秒

通过Date()函数获得。将得到的数字根据逻辑，绑定

给各div结构，实行动态旋转。点击按钮，改变背景颜色

---

3.3源码

html：

  Dark mode
 
   
     
     
     
     
   
      
      
  

css:

@import url('https://fonts.googleapis.com/css?family=Heebo:300&display=swap');

* {
  box-sizing: border-box;
}

:root {
  --primary-color: #000;
  --secondary-color: #fff;
}

html {
  transition: all 0.5s ease-in;
}

html.dark {
  --primary-color: #fff;
  --secondary-color: #333;
}

html.dark {
  background-color: #111;
  color: var(--primary-color);
}

body {
  font-family: 'Heebo', sans-serif;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  overflow: hidden;
  margin: 0;
}

.toggle {
  cursor: pointer;
  background-color: var(--primary-color);
  color: var(--secondary-color);
  border: 0;
  border-radius: 4px;
  padding: 8px 12px;
  position: absolute;
  top: 100px;
}

.toggle:focus {
  outline: none;
}

.clock-container {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
}

.clock {
  position: relative;
  width: 200px;
  height: 200px;
}

.needle {
  background-color: var(--primary-color);
  position: absolute;
  top: 50%;
  left: 50%;
  height: 65px;
  width: 3px;
  transform-origin: bottom center;
  transition: all 0.5s ease-in;
}

.needle.hour {
  transform: translate(-50%, -100%) rotate(0deg);
}

.needle.minute {
  transform: translate(-50%, -100%) rotate(0deg);
  height: 100px;
}

.needle.second {
  transform: translate(-50%, -100%) rotate(0deg);
  height: 100px;
  background-color: #e74c3c;
}

.center-point {
  background-color: #e74c3c;
  width: 10px;
  height: 10px;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  border-radius: 50%;
}

.center-point::after {
  content: '';
  background-color: var(--primary-color);
  width: 5px;
  height: 5px;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  border-radius: 50%;
}

.time {
  font-size: 60px;
}

.date {
  color: #aaa;
  font-size: 14px;
  letter-spacing: 0.3px;
  text-transform: uppercase;
}

.date .circle {
  background-color: var(--primary-color);
  color: var(--secondary-color);
  border-radius: 50%;
  height: 18px;
  width: 18px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  line-height: 18px;
  transition: all 0.5s ease-in;
  font-size: 12px;
}

js:

const hourEl = document.querySelector('.hour')
const minuteEl = document.querySelector('.minute')
const secondEl = document.querySelector('.second')
const timeEl = document.querySelector('.time')
const dateEl = document.querySelector('.date')
const toggle = document.querySelector('.toggle')

const days = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
const months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];

toggle.addEventListener('click', (e) => {
    const html = document.querySelector('html')
    if (html.classList.contains('dark')) {
        html.classList.remove('dark')
        e.target.innerHTML = 'Dark mode'
    } else {
        html.classList.add('dark')
        e.target.innerHTML = 'Light mode'
    }
})

function setTime() {
    const time = new Date();
    const month = time.getMonth()
    const day = time.getDay()
    const date = time.getDate()
    const hours = time.getHours()
    const hoursForClock = hours >= 13 ? hours % 12 : hours;
    const minutes = time.getMinutes()
    const seconds = time.getSeconds()
    const ampm = hours >= 12 ? 'PM' : 'AM'

    hourEl.style.transform = `translate(-50%, -100%) rotate(${scale(hoursForClock, 0, 12, 0, 360)}deg)`
    minuteEl.style.transform = `translate(-50%, -100%) rotate(${scale(minutes, 0, 60, 0, 360)}deg)`
    secondEl.style.transform = `translate(-50%, -100%) rotate(${scale(seconds, 0, 60, 0, 360)}deg)`

    timeEl.innerHTML = `${hoursForClock}:${minutes < 10 ? `0${minutes}` : minutes} ${ampm}`
    dateEl.innerHTML = `${days[day]}, ${months[month]} ${date}`
}

// StackOverflow https://stackoverflow.com/questions/10756313/javascript-jquery-map-a-range-of-numbers-to-another-range-of-numbers
const scale = (num, in_min, in_max, out_min, out_max) => {
    return (num - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}

setTime()

setInterval(setTime, 1000)

---

4.自制笔记本

---

4.1效果展示

---

4.2思路解析

通过js实现动态添加DOM结构，绑定创建出DOM结构的

添加，删除按钮。实现监听事件。实现动态改变DOM结构

其他的就是设置css的相关属性，

---

4.3源码

html：

       Add note
    
    

  

 css：

@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@200;400&display=swap');

* {
  box-sizing: border-box;
  outline: none;
}

body {
  background-color: #7bdaf3;
  font-family: 'Poppins', sans-serif;
  display: flex;
  flex-wrap: wrap;
  margin: 0;
  padding-top: 3rem;
}

.add {
  position: fixed;
  top: 1rem;
  right: 1rem;
  background-color: #9ec862;
  color: #fff;
  border: none;
  border-radius: 3px;
  padding: 0.5rem 1rem;
  cursor: pointer;
}

.add:active {
  transform: scale(0.98);
}

.note {
  background-color: #fff;
  box-shadow: 0 0 10px 4px rgba(0, 0, 0, 0.1);
  margin: 30px 20px;
  height: 400px;
  width: 400px;
  overflow-y: scroll;
}

.note .tools {
  background-color: #9ec862;
  display: flex;
  justify-content: flex-end;
  padding: 0.5rem;
}

.note .tools button {
  background-color: transparent;
  border: none;
  color: #fff;
  cursor: pointer;
  font-size: 1rem;
  margin-left: 0.5rem;
}

.note textarea {
  outline: none;
  font-family: inherit;
  font-size: 1.2rem;
  border: none;
  height: 400px;
  width: 100%;
  padding: 20px;
}

.main {
  padding: 20px;
}

.hidden {
  display: none;
}

js：

const addBtn = document.getElementById('add')

const notes = JSON.parse(localStorage.getItem('notes'))

if(notes) {
    notes.forEach(note => addNewNote(note))
}

addBtn.addEventListener('click', () => addNewNote())

function addNewNote(text = '') {
    const note = document.createElement('div')
    note.classList.add('note')

    note.innerHTML = `
    
        
        
    

    
    
    `

    const editBtn = note.querySelector('.edit')
    const deleteBtn = note.querySelector('.delete')
    const main = note.querySelector('.main')
    const textArea = note.querySelector('textarea')

    textArea.value = text
    main.innerHTML = marked(text)

    deleteBtn.addEventListener('click', () => {
        note.remove()

        updateLS()
    })

    editBtn.addEventListener('click', () => {
        main.classList.toggle('hidden')
        textArea.classList.toggle('hidden')
    })

    textArea.addEventListener('input', (e) => {
        const { value } = e.target

        main.innerHTML = marked(value)

        updateLS()
    })

    document.body.appendChild(note)
}

function updateLS() {
    const notesText = document.querySelectorAll('textarea')

    const notes = []

    notesText.forEach(note => notes.push(note.value))

    localStorage.setItem('notes', JSON.stringify(notes))
}

---

5.自定义写字台（也可自定义字的样式）

---

5.1效果展示

---

 5.2思路解析

搭建html结构,创建canvas标签，

绑定设置的结构比如+，-，颜色改变

动态设置并获取他的值，然后将这些值动态的

设置为canvas语法中设置渲染的宽度，以及设置

颜色的属性

---

5.3源码

html:

 
-
 10
 +
 
 X

css:

@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap');

* {
  box-sizing: border-box;
}

body {
  background-color: #f5f5f5;
  font-family: 'Roboto', sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
  margin: 0;
}

canvas {
  border: 2px solid steelblue;
}

.toolbox {
  background-color: steelblue;
  border: 1px solid slateblue;
  display: flex;
  width: 804px;
  padding: 1rem;
}

.toolbox > * {
  background-color: #fff;
  border: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  height: 50px;
  width: 50px;
  margin: 0.25rem;
  padding: 0.25rem;
  cursor: pointer;
}

.toolbox > *:last-child {
  margin-left: auto;
}

js:

const canvas = document.getElementById('canvas');
const increaseBtn = document.getElementById('increase');
const decreaseBtn = document.getElementById('decrease');
const sizeEL = document.getElementById('size');
const colorEl = document.getElementById('color');
const clearEl = document.getElementById('clear');

const ctx = canvas.getContext('2d');

let size = 10
let isPressed = false
colorEl.value = 'black'
let color = colorEl.value
let x
let y

canvas.addEventListener('mousedown', (e) => {
    isPressed = true

    x = e.offsetX
    y = e.offsetY
})

document.addEventListener('mouseup', (e) => {
    isPressed = false

    x = undefined
    y = undefined
})

canvas.addEventListener('mousemove', (e) => {
    if(isPressed) {
        const x2 = e.offsetX
        const y2 = e.offsetY

        drawCircle(x2, y2)
        drawLine(x, y, x2, y2)

        x = x2
        y = y2
    }
})

function drawCircle(x, y) {
    ctx.beginPath();
    ctx.arc(x, y, size, 0, Math.PI * 2)
    ctx.fillStyle = color
    ctx.fill()
}

function drawLine(x1, y1, x2, y2) {
    ctx.beginPath()
    ctx.moveTo(x1, y1)
    ctx.lineTo(x2, y2)
    ctx.strokeStyle = color
    ctx.lineWidth = size * 2
    ctx.stroke()
}

function updateSizeOnScreen() {
    sizeEL.innerText = size
}

increaseBtn.addEventListener('click', () => {
    size += 5

    if(size > 50) {
        size = 50
    }

    updateSizeOnScreen()
})

decreaseBtn.addEventListener('click', () => {
    size -= 5

    if(size < 5) {
        size = 5
    }

    updateSizeOnScreen()
})

colorEl.addEventListener('change', (e) => color = e.target.value)

clearEl.addEventListener('click', () => ctx.clearRect(0,0, canvas.width, canvas.height))

✍在最后，如果觉得博主写的还行，期待点赞  评论 收藏