js 保留小数点后两位。或小数点后为0的话 显示为整数

var num =2.446242342;  
num = num.toFixed(2); 
console.log(num); // 2.45
console.log(typeof num); // string

num = Math.floor(num * 100) / 100;
console.log(num); //2.44
console.log(typeof num); // number

var num =2.446242342;  
parseFloat(num)
console.log(parseFloat(num)); // 2.45
console.log(typeof num); // number

var num2 =6.00;  
parseFloat(num2)
console.log(parseFloat(num2)); // 6
console.log(typeof num2); // number