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JavaScript - Math.random() Method



The JavaScript Math.random() method returns a floating-point, pseudo-random number in the range 0 to less than 1 (inclusive of 0, but not 1) with approximately uniform distribution over that range.

For generating random number from uniform distribution over [a, b) range, where b>a, the following relationship can be used:

(b-a) * Math.random() + a

The implementation selects the initial seed to the random number generation algorithm. It cannot be chosen or reset by the user.

Syntax

Math.random();

Parameters

No parameter is required.

Return Value

Returns a floating-point, pseudo-random number between 0 (inclusive) and 1 (exclusive).

Example:

The example below shows the usage of Math.random() method.

var txt;

//generating a random number from [0,1)
txt = "Random number in [0,1) = " + 
         Math.random() + "<br>";
//generating a random number from [0,10)
txt = txt + "Random number in [0,10) = " + 
         (10*Math.random()) + "<br>";
//generating a random number from [5,10)
txt = txt + "Random number in [5,10) = " + 
         (5*Math.random()+5) + "<br>";
//generating a random number from [-5,10)
txt = txt + "Random number in [-5,10) = " + 
         (15*Math.random()-5) + "<br>";

The output (value of txt) after running above script will be:

Random number in [0,1) = 0.09260976329470672
Random number in [0,10) = 3.598471899689586
Random number in [5,10) = 5.529747793226086
Random number in [-5,10) = -0.6331544169820962

❮ JavaScript - Math Object

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