What is URL Encoding?

URLs (Uniform Resource Locators) identify resources on the web. However, not all characters can be used directly in a URL. URL encoding is the process of converting certain characters that are not allowed into a valid format. This ensures that the URL remains valid and can be transmitted across the internet without issues.

Characters such as spaces, punctuation marks, and non-ASCII characters must be encoded. URL encoding converts these characters into a percentage sign (%) followed by two hexadecimal digits that represent the ASCII value of the character.

For example, the space character ( ) is converted into %20, and the exclamation mark (!) is converted into %21.

Use Cases for URL Encoding

A common use case for URL encoding is when passing data in query parameters. For instance, if you want to pass the string "hello world!" as a query parameter in a URL, it should be encoded to avoid errors. The encoded query string would look like: ?search=hello%20world%21.

In JavaScript, URL encoding can be easily achieved using encodeURIComponent() or encodeURI() functions.

What is URL Decoding?

URL decoding is the process of reversing URL encoding. It converts the encoded characters back into their original form so they can be interpreted correctly. For example, the encoded string %20 is converted back to a space character ( ).

JavaScript provides the decodeURIComponent() and decodeURI() functions for decoding URL-encoded strings.

Conclusion

URL encoding and decoding are essential for ensuring that URLs remain valid when they contain special characters or spaces. Encoding allows URLs to be transmitted without causing errors, and decoding ensures the original characters are restored when needed.