SOURCE

function changeMoney(num) {
        if (Number(num) <= 1) return {
            num,
            unit: '元'
        };
        var moneyUnits = ["元", "万元", "亿元", "万亿"]
        var dividend = 10000;
        var curentNum = num;
        //转换数字 
        var curentUnit = moneyUnits[0];
        //转换单位 
        for (var i = 0; i < 4; i++) {
            curentUnit = moneyUnits[i]
            if (strNumSize(curentNum) < 5) {
                break;
            }
            curentNum = curentNum / dividend
        }
        var m = {
            num: 0,
            unit: ""
        }
        m.num = Number(curentNum).toFixed(2)
        m.unit = curentUnit;
        return m;
    }
function strNumSize(tempNum) {
        var stringNum = tempNum.toString()
        var index = stringNum.indexOf(".")
        var newNum = stringNum;
        if (index != -1) {
            newNum = stringNum.substring(0, index)
        }
        return newNum.length
    }

    const money = changeMoney(100)
    console.log(money)