A common decimal rounding function for JavaScript

The method of JavaScript decimal rounding.

Js:

The code is as follows	Copy Code
function Truncatenumber (n) { return n|0; }

Test:

The code is as follows	Copy Code
Console.log (Truncatenumber (12.345));

The browser prints out 12

In addition to the function above, there are

1) math.round (x)

The round () method can be rounded up by a number.

2) Math.floor (x)

The floor () method performs a downward rounding calculation, which returns an integer that is less than or equal to the function argument, and that is the nearest approximation.

3) Math.ceil (x)

The Ceil () method performs an upward rounding calculation, which returns an integer that is greater than or equal to the function argument, and that is the nearest.

Finally look at the comparison with the PHP rounding

1. Discard the fractional part and keep the whole number of parts
Php:intval (800.8)
Js:parseint (800.8)

2. Take up the whole, there are decimal numbers on the whole part plus 1
Php:ceil (800.8)
Js:Math.ceil (800.8)

3. Rounded.
Php:round (800.8)
Js:Math.round (800.8)

4, take the whole down.
Php:floor (800.8)
Js:Math.floor (800.8)

The following summary.

1. Discard the fractional part and keep the whole number of parts	parseInt(5/2)
2. Take up the whole, there are decimal numbers on the whole part plus 1	Math.ceil(5/2)
3, rounded.	Math.round(9/2)
4, take the whole down.	Math.floor(5/2)