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js实现数字滚动特效

2019-12-17 12:05 841 查看

本文实例为大家分享了js实现数字滚动展示的具体代码，供大家参考，具体内容如下

效果图

html代码

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
#t,#tt{
border: #ccc thin solid;
width: 250px;
height: 60px;
display: flex;
justify-content: space-around;
align-items: center;
font-size: 20px;
}
.t-num{
height: 100%;
overflow: hidden;
/*background-color: #ccc;*/
width: 25px;
line-height: 60px;
text-align: center;
}
.t-num-s{
display: block;
height: 100%;
width: 100%;
/*border: red thin solid;*/
}
</style>
</head>
<body>
<div id="t">

</div>
<div id="tt">

</div>
<!--结构示例-->
<!--<div>-->
<!--<div class="divClass"><span class="spanclass">1</span></div>-->
<!--<div class="divClass"><span class="spanclass">2</span></div>-->
<!--<div class="divClass"><span class="spanclass">3</span></div>-->
<!--<div class="divClass"><span class="spanclass">4</span></div>-->
<!--</div>-->
</body>
</html>
<script src="index.js"></script>
<script>
let num = 12345.5
//配置项 p:滚动熟读，height:数字容器的高度，spanclass：数字容器的classname,divClasss: span容器的class
// numchange.config({p: 5}).change('t', num)
let t = numchange()
t.change('t', num)
setInterval(() => {
num = Math.random() * 100 + parseFloat(num)
num = num.toFixed(2)
t.change('t', num)
},3000)

let num1 = 12345
let t1 = numchange()
t1.change('tt', num1)
setInterval(() => {
num1 = parseInt(Math.random() * 100) + parseInt(num1)
t1.change('tt', num1)
},3000)
</script>

js代码

let numchange = function (){
let point = '.'
// 数字容器高度
let height = 60
// 每次滚动距离/滚动速度
let p = 3
// 数字spanclass
let spanClass = 't-num-s'
// 数字divclass
let divClass = 't-num'
//
let cache = {}
function createDiv(id, num, len, paddingNum){
let str = ''
for (let i = 0; i < len; i++) {
str += `<div class="${divClass}" id="${id+i}"><span class="${spanClass}">${paddingNum === undefined?num[i]:paddingNum}</span></div>`
}
return str
}
function initZero(id, count){
document.getElementById(id).innerHTML = createDiv(id,null,count,0)
}
function refresh(oldNum, newNum, id){
let len = newNum.length - oldNum.length;
for (let i = 0; i < len; i++) {
oldNum.unshift('0')
}
document.getElementById(id).innerHTML = createDiv(id,oldNum,oldNum.length)
}
function refresh1(oldNum, newNum, id){
let len = oldNum.length - newNum.length;
for (let i = 0; i < len; i++) {
oldNum.shift()
}
document.getElementById(id).innerHTML = createDiv(id,oldNum,oldNum.length)
}
function scrollNum(id, num, order){
let h = num * height
let e = document.getElementById(id)
let t = setInterval(() => {
let m = e.scrollTop;
m = m + p
if(m > h){
clearInterval(t)
let cs = e.children
for (let i = cs.length-2; i >= 0; i--) {
e.removeChild(cs[i])
}
return
}
e.scrollTop = m
}, 10)
}
function createSpan(num){
let span = document.createElement('span')
span.className = spanClass
span.innerText = num
return span
}
function appendNum(id, start, end){
let f = document.createDocumentFragment()
let count = 0
if(start === end && isNaN(start)){
return 0
}
if(isNaN(start) && !isNaN(end)){
for (let i = 0; i <= end; i++) {
f.appendChild(createSpan(i))
count++
}
document.getElementById(id).appendChild(f)
return count
}
if(!isNaN(start) && isNaN(end)){
for (let i = start+1; i <= 9; i++) {
f.appendChild(createSpan(i))
count++
}
f.appendChild(createSpan('.'))
count++
document.getElementById(id).appendChild(f)
return count
}
if(start < end){
for (let i = start+1; i <= end; i++) {
f.appendChild(createSpan(i))
count++
}
}else if(start > end){
for (let i = start+1; i <= 9; i++) {
f.appendChild(createSpan(i))
count++
}
for (let i = 0; i <= end; i++) {
f.appendChild(createSpan(i))
count++
}
}else{
return 0
}
document.getElementById(id).appendChild(f)
return count
}

/**
* @param id 容器id
* @param num 展示的数字
*/
function change(id, num){
console.log(num)
let strArr = num.toString().split('');
let oldNum = cache[id]
// 如果没有缓存，开始数字全部填充0
if(!oldNum){
initZero(id,strArr.length)
oldNum = []
}else{
oldNum = cache[id].toString().split('')
// 如果新数字长，原来数字左侧填充0
if(oldNum.length < strArr.length){
refresh(oldNum, strArr, id)
// 如果新数字短，原来数字左侧移除
}else if(oldNum.length > strArr.length){
refresh1(oldNum, strArr, id)
}
}
// 循环比较每个数字差异，添加需要滚动的数字列
for (let i = 0, len = strArr.length; i < len; i++) {
let start = oldNum[i] !== point ? parseInt(oldNum[i]||0) : oldNum[i]
let end = strArr[i] !== point ? parseInt(strArr[i]||0) : strArr[i]
let count = appendNum(id+i, start, end)
if(count > 0){
// 数字滚动
scrollNum(id+i, count, i+1)
}
}
cache[id] = num
}

function config(param){
if(param.p){
p = param.p
}
if(param.height){
height = param.height
}
if(param.spanClass){
spanClass = param.spanClass
}
if(param.divClass){
divClass = param.divClass
}
return scroll
}

let scroll = {
change: change,
config: config
}
return scroll
}

遗留问题：setInterval方法在切换页面后，会变快。解决方案1：用setTimeout代替setInterval。2.requestAnimFrame

以上就是本文的全部内容，希望对大家的学习有所帮助

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标签： js 数字滚动

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