JavaScript Math.random() | Generate Random Number

The JavaScript Math.random() method is used when we need to generate a random number. This method generates/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 generated random number based on your choice:

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

JavaScript Math.random() Syntax

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

Math.random()

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

JavaScript generate random number from 1 to 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 to 100 without decimals

Now let me generate 10 random numbers between 1 to 100 without 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 above JavaScript example:

javascript 10 random numbers between 1 to 100

JavaScript Online Test


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