URLs can only be sent over the Internet using the ASCII character-set. Since URLs often contain characters outside the ASCII set, the URL has to be converted into ASCII. Encoding converts characters into a format that can be transmitted over the Internet.
URL encoding replaces non-ASCII characters with a "%" followed by hexadecimal digits. URLs cannot contain spaces, so encoding normally replaces a space with a plus (+) sign, or %20. For example, the encoded text for "This work is © by Marusya" might look something like this:
You have probably seen this, when you typed something and submitted it to a webpage. Sometimes you get a copy of what you submitted and it looks like this weird set of characters. This explains why.
