https://github.com/inorganik/countUp.js demo: http://inorganik.github.io/countUp.js/ 源码可以看这里
简单的使用示例：
<div id="box"></div>
<script src="../../../lib/countUp/countUp.js"></script>
<script type="text/javascript">
let options = {
useEasing: true,
useGrouping: false,
separator: ',',
decimal: '.',
};
let demo = new CountUp('box', 10, 0, 0, 2.5, options);
if (!demo.error) {
demo.start();
} else {
console.error(demo.error);
}
</script>说明：
var CountUp = function(target, startVal, endVal, decimals, duration, options)
// target = id of html element or var of previously selected html element where counting occurs
// startVal = the value you want to begin at
// endVal = the value you want to arrive at
// decimals = number of decimal places, default 0
// duration = duration of animation in seconds, default 2
// options = optional object of options (see below)
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
};