keepTwoDecimalFull(num, p) {

let result = parseFloat(num);

if (isNaN(result)) {

    alert('传递参数错误，请检查！');

    return false;

}

let multiplicator = Math.pow(10, p);

result = Math.round(num * multiplicator) / multiplicator;

let s_x = result.toString();

let pos_decimal = s_x.indexOf('.');

if (pos_decimal < 0) {

    pos_decimal = s_x.length;

    s_x += '.';

}

while (s_x.length <= pos_decimal + p) {

    s_x += '0';

}

return s_x;

}

很好用的一个封装函数

作者：噢是珊珊吖
链接：https://www.jianshu.com/p/d2965bcb3a36
来源：简书