Summary of Math.Round, parseint, Math.floor and Math.ceil decimal rounding in JS

Math.Round, parseint, Math.floor, and Math.ceil can all return an integer, depending on the difference, see the summary below.

First, Math.Round

Function: Rounding, returning parameter +0.5, rounding down.

Such as:

Math.Round (5.57)//return 6

Math.Round (2.4)//Return 2

Math.Round (-1.5)//return-1

Math.Round (-5.8)//return-6

Second, parseint

Function: Parses a string and returns an integer, which can be simply understood as the integer that returns the fractional part of the parameter.

Such as:

parseint (5.57)//Return 5

parseint (2.4)//Return 2

parseint (-1.5)//return-1

parseint (-5.8)//Return-5

Third, Math.floor

Function: Returns the largest integer less than or equal to the parameter.

Such as:

Math.floor (5.57)//Return 5

Math.floor (2.4)//Return 2

Math.floor (-1.5)//Return-2

Math.floor (-5.8)//return-6

Iv. Math.ceil

Function: Returns the smallest integer greater than or equal to the parameter

Math.ceil (5.57)//return 6

Math.ceil (2.4)//Return 3

Math.ceil (-1.5)//return-1

Math.ceil (-5.8)//Return-5

Summary of Math.Round, parseint, Math.floor and Math.ceil decimal rounding in JS