本文實例講述了JS實現滑動拼圖驗證功能。分享給大家供大家參考，具體如下：

先看一下效果圖：

設置畫布滑塊屬性

const l = 42, // 滑塊邊長 r = 10, // 滑塊半徑 w = 310, // canvas寬度 h = 155, // canvas高度 PI = Math.PIconst L = l + r * 2 // 滑塊實際邊長

設置背景圖片：

圖片鏈接地址可以自行更換

function getRandomImg() { return ’https://picsum.photos/300/150/?image=’ + getRandomNumberByRange(0, 100)}

CSS部分代碼：

.container { width: 310px; margin: 100px auto;}#msg { width: 100%; line-height: 40px; font-size: 14px; text-align: center;}a:link,a:visited,a:hover,a:active { margin-left: 100px; color: #0366D6;}.block { position: absolute; left: 0; top: 0;}.sliderContainer { position: relative; text-align: center; width: 310px; height: 40px; line-height: 40px; margin-top: 15px; background: #f7f9fa; color: #45494c; border: 1px solid #e4e7eb;}.sliderContainer_active .slider { height: 38px; top: -1px; border: 1px solid #1991FA;}.sliderContainer_active .sliderMask { height: 38px; border-width: 1px;}.sliderContainer_success .slider { height: 38px; top: -1px; border: 1px solid #52CCBA; background-color: #52CCBA !important;}.sliderContainer_success .sliderMask { height: 38px; border: 1px solid #52CCBA; background-color: #D2F4EF;}.sliderContainer_success .sliderIcon { background-position: 0 0 !important;}.sliderContainer_fail .slider { height: 38px; top: -1px; border: 1px solid #f57a7a; background-color: #f57a7a !important;}.sliderContainer_fail .sliderMask { height: 38px; border: 1px solid #f57a7a; background-color: #fce1e1;}.sliderContainer_fail .sliderIcon { background-position: 0 -83px !important;}.sliderContainer_active .sliderText,.sliderContainer_success .sliderText,.sliderContainer_fail .sliderText { display: none;}.sliderMask { position: absolute; left: 0; top: 0; height: 40px; border: 0 solid #1991FA; background: #D1E9FE;}.slider { position: absolute; top: 0; left: 0; width: 40px; height: 40px; background: #fff; box-shadow: 0 0 3px rgba(0, 0, 0, 0.3); cursor: pointer; transition: background .2s linear;}.slider:hover { background: #1991FA;}.slider:hover .sliderIcon { background-position: 0 -13px;}.sliderIcon { position: absolute; top: 15px; left: 13px; width: 14px; height: 10px; background: url(img/tb.png) 0 -26px; background-size: 34px 471px;}.refreshIcon { position: absolute; right: 0; top: 0; width: 34px; height: 34px; cursor: pointer; background: url(img/tb.png) 0 -437px; background-size: 34px 471px;}

頁面，頁面只用放一個div就可以了

<div class='container'> <div style='position: relative'></div></div>

js部分代碼，包括驗證是否正確

<script type='text/javascript'> (function(window) { const l = 42, // 滑塊邊長 r = 10, // 滑塊半徑 w = 310, // canvas寬度 h = 155, // canvas高度 PI = Math.PI const L = l + r * 2 // 滑塊實際邊長 function getRandomNumberByRange(start, end) { return Math.round(Math.random() * (end - start) + start) } function createCanvas(width, height) { const canvas = createElement(’canvas’) canvas.width = width canvas.height = height return canvas } function createImg(onload) { const img = createElement(’img’) img.crossOrigin = 'Anonymous' img.onload = onload img.onerror = () => { img.src = getRandomImg() } img.src = getRandomImg() return img } function createElement(tagName) { return document.createElement(tagName) } function addClass(tag, className) { tag.classList.add(className) } function removeClass(tag, className) { tag.classList.remove(className) } function getRandomImg() { return ’https://picsum.photos/300/150/?image=’ + getRandomNumberByRange(0, 100) } function draw(ctx, operation, x, y) { ctx.beginPath() ctx.moveTo(x, y) ctx.lineTo(x + l / 2, y) ctx.arc(x + l / 2, y - r + 2, r, 0, 2 * PI) ctx.lineTo(x + l / 2, y) ctx.lineTo(x + l, y) ctx.lineTo(x + l, y + l / 2) ctx.arc(x + l + r - 2, y + l / 2, r, 0, 2 * PI) ctx.lineTo(x + l, y + l / 2) ctx.lineTo(x + l, y + l) ctx.lineTo(x, y + l) ctx.lineTo(x, y) ctx.fillStyle = ’#fff’ ctx[operation]() ctx.beginPath() ctx.arc(x, y + l / 2, r, 1.5 * PI, 0.5 * PI) ctx.globalCompositeOperation = 'xor' ctx.fill() } function sum(x, y) { return x + y } function square(x) { return x * x } class jigsaw { constructor(el, success, fail) { this.el = el this.success = success this.fail = fail } init() { this.initDOM() this.initImg() this.draw() this.bindEvents() } initDOM() { const canvas = createCanvas(w, h) // 畫布 const block = canvas.cloneNode(true) // 滑塊 const sliderContainer = createElement(’div’) const refreshIcon = createElement(’div’) const sliderMask = createElement(’div’) const slider = createElement(’div’) const sliderIcon = createElement(’span’) const text = createElement(’span’) block.className = ’block’ sliderContainer.className = ’sliderContainer’ refreshIcon.className = ’refreshIcon’ sliderMask.className = ’sliderMask’ slider.className = ’slider’ sliderIcon.className = ’sliderIcon’ text.innerHTML = ’向右滑動滑塊填充拼圖’ text.className = ’sliderText’ const el = this.el el.appendChild(canvas) el.appendChild(refreshIcon) el.appendChild(block) slider.appendChild(sliderIcon) sliderMask.appendChild(slider) sliderContainer.appendChild(sliderMask) sliderContainer.appendChild(text) el.appendChild(sliderContainer) Object.assign(this, { canvas, block, sliderContainer, refreshIcon, slider, sliderMask, sliderIcon, text, canvasCtx: canvas.getContext(’2d’), blockCtx: block.getContext(’2d’) }) } initImg() { const img = createImg(() => { this.canvasCtx.drawImage(img, 0, 0, w, h) this.blockCtx.drawImage(img, 0, 0, w, h) const y = this.y - r * 2 + 2 const ImageData = this.blockCtx.getImageData(this.x, y, L, L) this.block.width = L this.blockCtx.putImageData(ImageData, 0, y) }) this.img = img } draw() { // 隨機創建滑塊的位置 this.x = getRandomNumberByRange(L + 10, w - (L + 10)) this.y = getRandomNumberByRange(10 + r * 2, h - (L + 10)) draw(this.canvasCtx, ’fill’, this.x, this.y) draw(this.blockCtx, ’clip’, this.x, this.y) } clean() { this.canvasCtx.clearRect(0, 0, w, h) this.blockCtx.clearRect(0, 0, w, h) this.block.width = w } bindEvents() { this.el.onselectstart = () => false this.refreshIcon.onclick = () => { this.reset() } let originX, originY, trail = [], isMouseDown = false this.slider.addEventListener(’mousedown’, function(e) { originX = e.x, originY = e.y isMouseDown = true }) document.addEventListener(’mousemove’, (e) => { if(!isMouseDown) return false const moveX = e.x - originX const moveY = e.y - originY if(moveX < 0 || moveX + 38 >= w) return false this.slider.style.left = moveX + ’px’ var blockLeft = (w - 40 - 20) / (w - 40) * moveX this.block.style.left = blockLeft + ’px’ addClass(this.sliderContainer, ’sliderContainer_active’) this.sliderMask.style.width = moveX + ’px’ trail.push(moveY) }) document.addEventListener(’mouseup’, (e) => { if(!isMouseDown) return false isMouseDown = false if(e.x == originX) return false removeClass(this.sliderContainer, ’sliderContainer_active’) this.trail = trail const { spliced, TuringTest } = this.verify() if(spliced) { if(TuringTest) { addClass(this.sliderContainer, ’sliderContainer_success’) this.success && this.success() } else { addClass(this.sliderContainer, ’sliderContainer_fail’) this.text.innerHTML = ’再試一次’ this.reset() } } else { alert('驗證失敗'); addClass(this.sliderContainer, ’sliderContainer_fail’) this.fail && this.fail();//驗證失敗后，1秒后重新加載圖片 setTimeout(() => { this.reset() }, 1000) } }) } verify() { const arr = this.trail // 拖動時y軸的移動距離 const average = arr.reduce(sum) / arr.length // 平均值 const deviations = arr.map(x => x - average) // 偏差數組 const stddev = Math.sqrt(deviations.map(square).reduce(sum) / arr.length) // 標準差 const left = parseInt(this.block.style.left) return { spliced: Math.abs(left - this.x) < 10, TuringTest: average !== stddev, // 只是簡單的驗證拖動軌跡，相等時一般為0，表示可能非人為操作 } } reset() { this.sliderContainer.className = ’sliderContainer’ this.slider.style.left = 0 this.block.style.left = 0 this.sliderMask.style.width = 0 this.clean() this.img.src = getRandomImg() this.draw() } } window.jigsaw = { init: function(element, success, fail) { new jigsaw(element, success, fail).init() } } }(window)) jigsaw.init(document.getElementById(’captcha’), function() { alert('驗證成功'); })</script>

更多關于JavaScript相關內容感興趣的讀者可查看本站專題：《JavaScript圖片操作技巧大全》、《JavaScript切換特效與技巧總結》、《JavaScript運動效果與技巧匯總》、《JavaScript動畫特效與技巧匯總》、《JavaScript錯誤與調試技巧總結》、《JavaScript數據結構與算法技巧總結》、《JavaScript遍歷算法與技巧總結》及《JavaScript數學運算用法總結》

希望本文所述對大家JavaScript程序設計有所幫助。