超过4位截取保留4位，不足4位保留原位数不补0
//保留4位小数 var number = 12.3321432; number = String(number).replace(/^(.*\..{4}).*$/,"$1"); number = Number(number); // number = 12.3321 //保留2位小数 var reg = /^(.*\..{2}).*$/; var number2 = 12.3; number2 = String(number2).replace(reg ,"$1"); number2 = Number(number2); // number2 = 12.3 不足保留位数不补0
超过4位截取保留4位，不足4位补足0
getFloat = function(number, n) { n = n ? parseInt(n) : 0; if(n <= 0) { return Math.round(number); } number = Math.round(number * Math.pow(10, n)) / Math.pow(10, n); //四舍五入 number = Number(number).toFixed(n); //补足位数 return number; }; console.log(getFloat('0', 4)); //0.0000 console.log(getFloat('2.08', 4)); //2.0800 console.log(getFloat('2.08500', 4)); //2.0850 console.log(getFloat('2.08996', 4)); //2.0900 console.log(getFloat('2.08994', 4)); //2.0899
toFixed()方法
var a =123.456789; alert(a.toFixed(4));// 四舍五入保留四位小数
需注意，保留两位小数，将数值类型的数据改变成了字符串类型
Math.floor()向下取整
let numBoolean = Math.floor((this.editFormData.amount / this.thresholdYuan) * 10000) / 10000 >= 0.005
返回true或false
