Octal Integer

For an octal literal, the first digit must be a zero (0). The octal literal can have numbers from 0 to 7.

 
<!DOCTYPE html>
<html>
<head>
    <title>Octal Number Example</title>
    <script type="text/javascript">
          
       var octalNum = 053; 
              
       document.writeln(octalNum);//octal for 43 
    </script>

</head>
<body>
  
</body>
</html>

Click to view the demo

If a number out of 0 to 7 is used, then the leading zero is ignored and the number is considered as a decimal.

 
<!DOCTYPE html>
<html>
<head>
    <title>Octal Number Example</title>
    <script type="text/javascript">
          
       var octalNum = 079; //invalid octal
              
       document.writeln(octalNum); //79
    </script>

</head>
<body>
  
</body>
</html>

Click to view the demo

Octal literals are invalid in strict mode.

The octal numbers are converted to decimal numbers in all arithmetic operations.

 
<!DOCTYPE html>
<html>
<head>
    <title>Octal Number Example</title>
    <script type="text/javascript">
          
       var octalNum = 056; 

       document.writeln(octalNum); //46
       
       var aNum = 123; 
       
       document.writeln(octalNum + aNum); //169
    </script>

</head>
<body>
  
</body>
</html>

Click to view the demo