Windows 10 reached EOS (end of support) on October 14, 2025. If you are on Windows 10, see this article.

Avatar for Username

Шукати в статтях підтримки

Остерігайтеся нападів зловмисників. Mozilla ніколи не просить вас зателефонувати, надіслати номер телефону у повідомленні або поділитися з кимось особистими даними. Будь ласка, повідомте про підозрілі дії за допомогою меню “Повідомити про зловживання”

Докладніше
Ця тема закрита і перенесена в архів. Якщо вам потрібна допомога, запитайте.
Locked Архівовано

HTML page content type has charset=iso-8859-1 but document.characterSet is 'UTF-8'

Firefox Інше
SuMo Bot відповів
SuMo Bot
SuMo Bot

Hi,

I'm a web developer and I have an issue document.characterSet property from DOM API has an incorrect value on a non UTF-8 page

Firefox version: 95.0.2

1. HTML page is returned with following content-type content-type: text/html; charset=iso-8859-1

2. JavaScript code in the page reads document.characterSet property

Expected characterSet value is "ISO-8859-1"

Actual characterSet value is "UTF-8"

Thanks and regards,

Hi, I'm a web developer and I have an issue document.characterSet property from DOM API has an incorrect value on a non UTF-8 page Firefox version: 95.0.2 1. HTML page is returned with following content-type content-type: text/html; charset=iso-8859-1 2. JavaScript code in the page reads document.characterSet property Expected characterSet value is "ISO-8859-1" Actual characterSet value is "UTF-8" Thanks and regards,

Усі відповіді (2)

cor-el
cor-el
  • Топ-25 помічників
  • Модератор

What encoding does the server send ?

If the server sends encoding "UTF-8" then that prevails and Firefox ignores a possible specification in the actual file for security reasons.

SuMo Bot
SuMo Bot Автор питання

I observed this behavior while working on a customer incident. The server responds with a content-type header which is "text/html; charset=iso-8859-1"

I tried to reproduce on a sample but in my test, I get the expected "window-1252".

However, if the response body contains an UTF-8 BOM, content-type header is ignored and document characterSet is "UTF-8"

Here is a small sample https://glitch.com/edit/#!/document-charset

Is this the intended behavior?

SuMo Bot
SuMo Bot Автор питання

This question has been locked because the original author has deleted their account. While you can no longer post new replies, the existing content remains available for reference.