btoa/atob(string)

These functions convert between binary strings and base64-encoded ASCII strings, useful for data encoding and decoding operations.

btoa() - Binary to ASCII

Encodes a string of data to base64.

encoded = btoa("Hello, world!")
log encoded  // "SGVsbG8sIHdvcmxkIQ=="

Syntax

btoa(content)

Parameters

• content: String - The string data to be encoded to base64

Return Value

Returns a base64-encoded ASCII string.

atob() - ASCII to Binary

Decodes a base64-encoded string back to its original form.

decoded = atob("SGVsbG8sIHdvcmxkIQ==")
log decoded  // "Hello, world!"

Syntax

atob(content)

Parameters

• content: String - The base64-encoded string to be decoded

Return Value

Returns the decoded string.

Use Cases

These functions are particularly useful for:

• Encoding binary data to be transmitted as text

• Working with data URLs

• Storing binary data in text-based formats

• Handling image data in data URI format

• Basic data obfuscation (not for security purposes)

Examples

Data URI Creation

// Create a simple data URI for an image
dataURI = "data:image/png;base64," + btoa(imageBinaryData)

// Then use it in an image element
image dataURI 100 100

Simple Text Encoding/Decoding

// Encode a user message
message = "This is a secret message"
encoded = btoa(message)
log encoded  // Base64 encoded version

// Later decode it
original = atob(encoded)
log original  // "This is a secret message"

Working with APIs that Return Base64

// Some API returns base64 data
apiResponse = fetchData("https://api.example.com/image")

// Decode it
decodedData = atob(apiResponse)

// Process the decoded data
// ...

Notes

• These functions work with strings, not arbitrary binary data

• For full Unicode support, you may need additional handling

• Not suitable for encrypting sensitive data

• Very large strings may cause performance issues

• If the input to atob() is not a valid base64 string, it will throw an error