Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Natao arisiva ity resaka mitohy ity. Mametraha fanontaniana azafady raha mila fanampiana.

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

  • 2 valiny
  • 2 manana an'ity olana ity
  • 5 views
  • Valiny farany nomen'i gilles.poirot

gilles.poirot
gilles.poirot
more options

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,

All Replies (2)

cor-el
cor-el
  • Moderator
  • Top 10 Contributor
more options

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.

gilles.poirot
gilles.poirot Tompon'ny fanontaniana
more options

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?