JavaScript Math.random(): Generate Random Number

The JavaScript Math.random() method is used when we need to generate a random number. This method generates or returns a random number between 0 and 1, where 0 is included and 1 is not. For example:

HTML with JavaScript Code

<!DOCTYPE html>
<html>
<body>

   <p id="xyz"></p>

  <script>
    let randomNum = Math.random();
    document.getElementById("xyz").innerHTML = randomNum;
  </script>
   
</body>
</html>

Output

Now you can use any of the following methods to round the randomly generated number based on your choice:

Math.ceil(): rounds a number up to its nearest largest integer.
Math.floor(): rounds a number up to its nearest smallest integer.
Math.round(): rounds a specified number to its nearest integer value.
toFixed(): round a number to a particular number of decimals.
toPrecision(): format a number to a specific length.
Math.trunc(): find the integer part of a number.

These methods are described in the Math Object post.

JavaScript Math.random() Syntax

The syntax of the Math.random() method in JavaScript is:

Math.random()

It returns a number that ranges from 0 (inclusive) to 1 (exclusive).

JavaScript generates a random number from 1 to 100

The following code generates and prints a random number between 1 and 100.

HTML with JavaScript Code

<!DOCTYPE html>
<html>
<body>

   <p id="xyz"></p>

  <script>
    document.getElementById("xyz").innerHTML = Math.random() * 100;
  </script>
   
</body>
</html>

Output

Find 10 random numbers between 1 and 100 without decimals

Now let me generate 10 random numbers between 1 and 100 without the decimal part:

HTML with JavaScript Code

<!DOCTYPE html>
<html>
<body>

  <script>
    let rn;
    for(let i=0; i<10; i++)
    {
      rn = Math.random() * 100;
      console.log(Math.trunc(rn));
    }
  </script>
   
</body>
</html>

The snapshot given below shows the sample output produced by the above JavaScript example:

javascript 10 random numbers between 1 to 100

JavaScript Online Test

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