Differences between JavaScript math. Ceil and math. Round and math. Floor

Difference between JavaScript math. Ceil () and math. Round () and math. Floor:

Math. Ceil () rounded up

Alert (math. Ceil (20.1) // Output 21 alert (math. Ceil (20.5) // Output 21 alert (math. Ceil (20.9) // Output 21

Math. Round standard rounding

Alert (math. Round (20.1) // output 20 alert (math. Round (20.5) // Output 21 alert (math. Round (20.9) // Output 21

Math. Floor () rounding down

Alert (math. Floor (20.1) // output 20 alert (math. Floor (20.5) // output 20 alert (math. Floor (20.9) // output 20