本篇文章为大家展示了使用CountUp.js怎么实现一个数字滚动增值效果，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。
js文件
var CountUp = function (target, startVal, endVal, decimals, duration, options) {
var self = this
self.version = function () { return '1.9.3' }
// default options
self.options = {
useEasing: true, // toggle easing
useGrouping: true, // 1,000,000 vs 1000000
separator: ',', // character to use as a separator
decimal: '.', // character to use as a decimal
easingFn: easeOutExpo, // optional custom easing function, default is Robert Penner's easeOutExpo
formattingFn: formatNumber, // optional custom formatting function, default is formatNumber above
prefix: '', // optional text before the result
suffix: '', // optional text after the result
numerals: [] // optionally pass an array of custom numerals for 0-9
}
// extend default options with passed options object
if (options && typeof options === 'object') {
for (var key in self.options) {
if (options.hasOwnProperty(key) && options[key] !== null) {
self.options[key] = options[key]
}
}
}
if (self.options.separator === '') {
self.options.useGrouping = false
} else {
// ensure the separator is a string (formatNumber assumes this)
self.options.separator = '' + self.options.separator
}
// make sure requestAnimationFrame and cancelAnimationFrame are defined
// polyfill for browsers without native support
// by Opera engineer Erik Möller
var lastTime = 0
var vendors = ['webkit', 'moz', 'ms', 'o']
for (var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
window.requestAnimationFrame = window[vendors[x] + 'RequestAnimationFrame']
window.cancelAnimationFrame = window[vendors[x] + 'CancelAnimationFrame'] || window[vendors[x] + 'CancelRequestAnimationFrame']
}
if (!window.requestAnimationFrame) {
window.requestAnimationFrame = function (callback, element) {
var currTime = new Date().getTime()
var timeToCall = Math.max(0, 16 - (currTime - lastTime))
var tesult = currTime + timeToCall
var id = window.setTimeout(function () { callback(tesult) }, timeToCall)
lastTime = currTime + timeToCall
return id
}
}
if (!window.cancelAnimationFrame) {
window.cancelAnimationFrame = function (id) {
clearTimeout(id)
}
}
function formatNumber (num) {
var neg = (num < 0)
var x, x1, x2, x3, i, len
num = Math.abs(num).toFixed(self.decimals)
num += ''
x = num.split('.')
x1 = x[0]
x2 = x.length > 1 ? self.options.decimal + x[1] : ''
if (self.options.useGrouping) {
x3 = ''
for (i = 0, len = x1.length; i < len; ++i) {
if (i !== 0 && ((i % 3) === 0)) {
x3 = self.options.separator + x3
}
x3 = x1[len - i - 1] + x3
}
x1 = x3
}
// optional numeral substitution
if (self.options.numerals.length) {
x1 = x1.replace(/[0-9]/g, function (w) {
return self.options.numerals[+w]
})
x2 = x2.replace(/[0-9]/g, function (w) {
return self.options.numerals[+w]
})
}
return (neg ? '-' : '') + self.options.prefix + x1 + x2 + self.options.suffix
}
// Robert Penner's easeOutExpo
function easeOutExpo (t, b, c, d) {
return c * (-Math.pow(2, -10 * t / d) + 1) * 1024 / 1023 + b
}
function ensureNumber (n) {
return (typeof n === 'number' && !isNaN(n))
}
self.initialize = function () {
if (self.initialized) return true
self.error = ''
self.d = (typeof target === 'string') ? document.getElementById(target) : target
if (!self.d) {
self.error = '[CountUp] target is null or undefined'
return false
}
self.startVal = Number(startVal)
self.endVal = Number(endVal)
// error checks
if (ensureNumber(self.startVal) && ensureNumber(self.endVal)) {
self.decimals = Math.max(0, decimals || 0)
self.dec = Math.pow(10, self.decimals)
self.duration = Number(duration) * 1000 || 2000
self.countDown = (self.startVal > self.endVal)
self.frameVal = self.startVal
self.initialized = true
return true
} else {
self.error = '[CountUp] startVal (' + startVal + ') or endVal (' + endVal + ') is not a number'
return false
}
}
// Print value to target
self.printValue = function (value) {
var result = self.options.formattingFn(value)
if (self.d.tagName === 'INPUT') {
this.d.value = result
} else if (self.d.tagName === 'text' || self.d.tagName === 'tspan') {
this.d.textContent = result
} else {
this.d.innerHTML = result
}
}
self.count = function (timestamp) {
if (!self.startTime) { self.startTime = timestamp }
self.timestamp = timestamp
var progress = timestamp - self.startTime
self.remaining = self.duration - progress
// to ease or not to ease
if (self.options.useEasing) {
if (self.countDown) {
self.frameVal = self.startVal - self.options.easingFn(progress, 0, self.startVal - self.endVal, self.duration)
} else {
self.frameVal = self.options.easingFn(progress, self.startVal, self.endVal - self.startVal, self.duration)
}
} else {
if (self.countDown) {
self.frameVal = self.startVal - ((self.startVal - self.endVal) * (progress / self.duration))
} else {
self.frameVal = self.startVal + (self.endVal - self.startVal) * (progress / self.duration)
}
}
// don't go past endVal since progress can exceed duration in the last frame
if (self.countDown) {
self.frameVal = (self.frameVal < self.endVal) ? self.endVal : self.frameVal
} else {
self.frameVal = (self.frameVal > self.endVal) ? self.endVal : self.frameVal
}
// decimal
self.frameVal = Math.round(self.frameVal * self.dec) / self.dec
// format and print value
self.printValue(self.frameVal)
// whether to continue
if (progress < self.duration) {
self.rAF = requestAnimationFrame(self.count)
} else {
if (self.callback) self.callback()
}
}
// start your animation
self.start = function (callback) {
if (!self.initialize()) return
self.callback = callback
self.rAF = requestAnimationFrame(self.count)
}
// toggles pause/resume animation
self.pauseResume = function () {
if (!self.paused) {
self.paused = true
cancelAnimationFrame(self.rAF)
} else {
self.paused = false
delete self.startTime
self.duration = self.remaining
self.startVal = self.frameVal
requestAnimationFrame(self.count)
}
}
// reset to startVal so animation can be run again
self.reset = function () {
self.paused = false
delete self.startTime
self.initialized = false
if (self.initialize()) {
cancelAnimationFrame(self.rAF)
self.printValue(self.startVal)
}
}
// pass a new endVal and start animation
self.update = function (newEndVal) {
if (!self.initialize()) return
newEndVal = Number(newEndVal)
if (!ensureNumber(newEndVal)) {
self.error = '[CountUp] update() - new endVal is not a number: ' + newEndVal
return
}
self.error = ''
if (newEndVal === self.frameVal) return
cancelAnimationFrame(self.rAF)
self.paused = false
delete self.startTime
self.startVal = self.frameVal
self.endVal = newEndVal
self.countDown = (self.startVal > self.endVal)
self.rAF = requestAnimationFrame(self.count)
}
// format startVal on initialization
if (self.initialize()) self.printValue(self.startVal)
}
module.exports = CountUpindex.html文件中需要进入该插件，和jq插件，再进行new实例化
var options = {
useEasing: true, // 使用缓和效果
useGrouping: true, // 使用分组效果
separator: ',', // 分离器，数据够三位，例如100,000
decimal: '.', // 小数点分割，例如：10.00
prefix: '', // 第一位默认数字，例如：¥
suffix: '' // 最后一位默认数字，例如：元，美元
}
// new CountUp(target, startVal, endVal, decimals, duration, options)
// target = 目标元素的 ID
// startVal = 开始值
// endVal = 结束值
// decimals = 小数位数 默认值是0
// duration = 动画延迟秒数，默认值是2；
// options = optional object of options (see below)
var demo = new CountUp('extractionMoney', 0, data.balanceAmount, 2, 0.5, options)
if (!demo.error) {
demo.start()
} else {
console.error(demo.error)
}上述内容就是使用CountUp.js怎么实现一个数字滚动增值效果，你们学到知识或技能了吗？如果还想学到更多技能或者丰富自己的知识储备，欢迎关注创新互联成都网站设计公司行业资讯频道。
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