JavaScript Random
Math.random()
Math.random() returns a random number between 0 (inclusive), and 1
(exclusive):
Math.random() always returns a number lower than 1.
JavaScript Random Integers
Math.random() used with Math.floor() can be used to return random integers.
Example
Math.floor(Math.random() * 101); // returns a
random integer from 0 to 100
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Example
Math.floor(Math.random() * 10) + 1; // returns a random integer from 1
to 10
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Example
Math.floor(Math.random() * 100) + 1; // returns a random integer from 1 to 100
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A Proper Random Function
As you can see from the examples above, it might be a good idea to create a proper random function to use for all random integer purposes.
This JavaScript function always returns a random number between min (included) and max (excluded):
Example
function getRndInteger(min, max) {
return Math.floor(Math.random() * (max - min) ) + min;
}
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This JavaScript function always returns a random number between min and max (both included):
Example
function getRndInteger(min, max) {
return Math.floor(Math.random() * (max - min + 1) ) + min;
}
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