# How to use the parseInt() function in JavaScript

The `parseInt()`

function is one of the most commonly used functions in JavaScript. It is used to convert a string into a number. The function can take a number of different parameters, but the most common is the string to be converted and the base of the number.

The basic usage of the `parseInt()`

function is:

```
parseInt(string, base)
```

The first parameter is the string to be converted into a number. The second parameter is the base of the number. The base can be any number between 2 and 36. The base 10 is the most common, so that is the default if the base is not specified.

The `parseInt()`

function will return the number that is represented by the string in the given base. If the string cannot be converted into a number in the given base, then the function will return `NaN`

(Not a Number).

Here is an example of the `parseInt()`

function being used:

```
var string = "24";
var base = 10;
var number = parseInt(string, base);
console.log(number);
```

This code will print the number 24. The string "24" is converted into the number 24 in base 10.

The `parseInt()`

function can also be used to convert hexadecimal numbers into integers. The hexadecimal number system uses the letters A through F to represent the numbers 10 through 15. Here is an example of the function being used to convert a hexadecimal number into an integer:

```
var string = "AF";
var base = 16;
var number = parseInt(string, base);
console.log(number);
```

This code will print the number 255. The string "AF" is converted into the number 255 in base 16.

The `parseInt()`

function can also be used to convert binary numbers into integers. The binary number system uses the numbers 0 and 1 to represent the numbers 2 and 10. Here is an example of the function being used to convert a binary number into an integer:

```
var string = "1101";
var base = 2;
var number = parseInt(string, base);
console.log(number);
```

This code will print the number 25. The string "1101" is converted into the number 25 in base 2.