Why does a Chinese URL turn into a long string like %E5%8F%B0 when you copy and paste it?

Question

Weirdo · Accepted Answer

It is the UTF-8 encoding of the Chinese characters. URLs only allow a small set of ASCII characters, so each Chinese character is converted to UTF-8 bytes and every byte is written as % plus two hex digits — 「台」 becomes %E5%8F%B0. The link is not broken; it opens the same page.

RFC 3986, the generic URI syntax, defines a small set of characters that can appear as-is: letters, digits and a few symbols. Anything else is written with percent-encoding: a % followed by two hexadecimal digits that stand for one byte. The RFC also says text made of non-ASCII characters should first be encoded as UTF-8 bytes, which are then percent-encoded one by one.

Common Chinese characters take 3 bytes in UTF-8, so each one turns into three %XX groups, nine characters in total. 「台灣」 becomes %E5%8F%B0%E7%81%A3 and 「天氣」 becomes %E5%A4%A9%E6%B0%A3. MDN describes encodeURIComponent() the same way: each character is replaced by one to four escape sequences representing its UTF-8 encoding.

Browsers decode the URL for display so it stays readable, but what gets sent and copied is the encoded form. That is why pasting into LINE, Word or a form produces a wall of percent signs. Both forms point to the same page; if you want it readable for others, add the page title next to it or use a short link.

Why does a Chinese URL turn into a long string like %E5%8F%B0 when you copy and paste it?

URLs never accepted Chinese directly

One character usually becomes nine

Why the address bar still shows Chinese