Generating Random Numbers With Math.random() Javascript

The JavaScript function Math.random() randomly generates a number from 0 to slightly less than 1 (shown as <1).

Generate random numbers from 0 to <3
Math.random() * 3

This gets us numbers from 1 to <3
Math.random() * 2 + 1

Math.random() is explained more here.

Use Math.floor() to round numbers downward to the nearest integer:

Math.floor(Math.random()*3+1)
will get a whole number between 1 and 3

To generate random numbers between 1 and max —
Math.floor(Math.random()*max+1)

This article discusses how to generate a random negative number or a random number between a range including both negative and positive numbers. Here is the basic rule:

For negative values from -9 to 0 subtract 9 from the previous result:

var negativeRandomN = Math.floor(Math.random()*10) – 9

To generate a random integer from m to n:

var randomN = Math.floor(Math.random() * (n-m+1)) + m

This entry was posted in Javascript, Uncategorized and tagged , , . Bookmark the permalink.

Comments are closed.