[JavaScript]数字取小数点后固定位数

object.toFixed([n])

1. 舍弃规则为四舍五入
2. object必须为数字,若为字符串会报异常Uncaught TypeError: test.toFixed is not a function
   

   
    var test = "100";
    test.toFixed(1);
    

3. 若参数为空,默认位数为0
   

   
    var test = "100";
    test = parseInt(test);
    test.toFixed();
    console.log(test);
    

   
   结果为:100
4. 参数范围为[0, 20],若超出范围为会报异常Uncaught RangeError: toFixed() digits argument must be between 0 and 20
   

   
    var test = "100";
    test = parseInt(test);
    test.toFixed(21);
    console.log(test);