URLs need to be formatted with ASCII characters in order for browsers to correctly interpret them.

There are sets of characters that serve a specific purpose within a URL. For example, "/" is used to separate domains and directories and "?" is used to separate query strings.

":" | "/" | "#" | "?" | "&" | "@" | "%" | "+" | "~" | ";" | "=" | "$" | ","

If any of these characters are used within a URL for any purpose outside of what they're supposed to be used for, they'll need to be encoded. For example, this may happen when these characters form part of a URL within a query parameter ("?"):

• https://ad.atdmt.com/example.html?query1=abc:123

In this example, the colon ":" is being used within a query parameter and therefore should be encoded in order for this URL to be correctly interpreted by the browser.

As a result, the encoded version of the this URL is:

• https://ad.atdmt.com/example.html?query1=abc%3A123

Encoding involves escaping these characters followed by their hexadecimal (two-character) equivalent value, as defined within the US ASCII character set. Escaping is denoted by the percentage sign character "%".

The hex value for ":" is 3A so the complete encoded version of this character becomes %3A.

Learn more about preparing tags.

* Nguồn: Facebook