数字类型操作方法

JS获取number类型长度

方法一：调用toString方法转为字符串后取长度
var num = 123;
alert(num.toString().length);
方法二：隐式转字符串后取长度
var num = 123;
alert((num + ‘’).length)

JavaScript中string转换成number

var a = " 42";
var b = " 42mm";
var c = "0xff";
var d = "42.34";
console.log(Number(a));//42
console.log(Number(b));//NaN
console.log(Number(c));//255
console.log(Number(d));//42.34

js保留两位小数

var num =2.446242342;
num = num.toFixed(2); // 输出结果为 2.45

向上取整+转字符串

Math.ceil(result[4]*225).toString()