### Octals and Hexadecimals

 JavaScript FAQ | JavaScript Numbers FAQ

Question: Is there a way to use octal and hexadecimal numbers in JavaScript?

Answer: Yes, in JavaScript you can use octals and hexadecimals.

The following are examples of octal numbers:
`01234 ` `-077 ` `0312 `
Positive octal numbers must begin with `0` (zero) followed by octal digit(s).
Negative octal numbers must begin with `-0` followed by octal digit(s).

And these are examples of hexadecimal numbers:
`0xFF ` `-0xCCFF ` `0xabcdef `
Positive hexadecimals must begin with `0x` and negative hexadecimals must begin with `-0x`.

When you need to convert an octal or hexadecimal string to a number, use the function `parseInt(str,base)`. Consider these examples:

```octalStr='377';
num = parseInt(octalStr,8);  // num now holds 255

hexStr='7F';
num = parseInt(hexStr,16);   // num now holds 127
```
The second argument of `parseInt` specifies the base of the number whose representation is contained in the original string. This argument can be any integer from 2 to 36.

See also:

• Converting numbers to another base
• Mathematical functions in JavaScript
• Random numbers in JavaScript
• Rounding in JavaScript
• Accuracy of JavaScript arithmetic
• Can I display mathematical symbols as part of JavaScript output?
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