
Javascript round to 2 decimal and any decimal places, with keeping or no when returning integers
Javascript round decimal is implemented with the Math.round() and toFixed() methods; the former can only take the integer part, and all decimals are discarded; if you want to round the specified decimal places, you must add some auxiliary code. the latter can arbitrarily round the decimal places. The following first introduces the simple usage of Math.round() and toFixed(), and then introduces encapsulate them into methods to call directly.
I, The method of javascript round decimal
1. Method:
Math.round(d);//d is any valid value
NumberObject.toFixed(len);//len is the number of decimal places to be rounded
2. Examples of Math.round (Round to integer):
Math.round(2.4);//Output: 2
Math.round(2.5);//Output: 3
Math.round(2.44);//Output: 2
Math.round(2.54);//Output: 3
Math.round(2.455);//Output: 2
As can be seen from the output, the round() method only looks at whether the number after the decimal point is greater than or equal to 5; if it is, carries 1 to the number before it; if it is not, it does not carry 1 to the number before it regardless of whether its following numbers are greater than or equal to 5.
3. Examples of NumberObject.toFixed (Round to the specified number of decimal places):
var num = 2.4893;
num.toFixed(2);//Javascript round to 2 decimal places, output: 2.49
num.toFixed(3);//Javascript round to 3 decimal places, output: 2.489
num.toFixed(1);//Javascript round to 1 decimal place, output: 2.5
II, How to round off decimal numbers in javascript, it does not keep decimal places when returning integers
Math.round() can not keep decimal places, so to keep the specified decimal places (such as 2, 3, etc.), but also add a few codes, the implementation method is as follows:
//When returning an integer, no decimal places are kept, for example, 2.999, 2 decimal places are reserved, and 3 is returned
//num: value to be rounded, len: decimal places are kept
function GetRound(num, len) {
return Math.round(num * Math.pow(10, len)) / Math.pow(10, len);
}
Call:
GetRound(2.999, 2);//Round to 2 decimal places, return 3
GetRound(2.989, 2);//Round to 2 decimal places, return 2.99
III, Javascript round decimal keeps decimal places in any case
//Round to the specified decimal places, for example, 2.999, round to 2 decimal places, return 3.00
//num: value to be rounded, len: decimal places are kept
function GetRoundDd(num, len) {
return num.toFixed(len);
}
Call:
GetRoundDd(2.999, 2);//Round to 2 decimal places, return 3.00
GetRoundDd(2.989, 2);//Round to 2 decimal places, return 2.99
-
Related Reading
- Javascript get current url, domain from url, relativ
- Remove html element javascript by their parent or cl
- C# label control, with winforms label transparent ba
- Javascript get all input elements in form and all im
- Javascript create element(div,li,img,span) dynamical
- Css rotate image, background image and text only, wi
- How to round numbers in excel and fix rounding error
- Javascript img src path changes, with without id (ge
- How to use round function in excel with formula(8 fu
- Javascript show hide div onclick, onclick radio butt
- Javascript get element height and width, with div, u
- Css transition background color highlight, gradient