Links generated automatically

From MozillaZine Knowledge Base

This article was written for Thunderbird but also applies to Mozilla Suite / SeaMonkey (though some menu sequences may differ).

This article describes the links that Thunderbird generates automatically. For example, when you write a message and type, someone who receives the message sees a link to: (typically blue and underlined, but without the "external link" icon that this knowledge base adds).

The developers' jargon for this process is that the text has been linkified (made into a link).


What Thunderbird linkifies

Thunderbird linkifies anything that looks as if it is a URL—that is, if it starts with a protocol scheme that Thunderbird recognises. Some examples of protocol schemes are: http:, https:, ftp:, mailto:, about:, mailbox:, webcal:

Thunderbird also linkifies anything that looks as if it is an incomplete URL, including things that look as if they are e-mail addresses. In these cases Thunderbird adds a protocol scheme to complete the URL. The only protocol schemes that Thunderbird adds are:

mailto: Text that looks like an e-mail address
http:// Text that begins www. and looks like a web page
ftp:// Text that begins ftp. and looks like an FTP site

When Thunderbird linkifies

Thunderbird linkifies HTML when you send or save the message. Thunderbird linkifies plain text when you display the message.

If you send a multipart message, Thunderbird linkfies the HTML part but not the plain text part.

If you read an HTML message as plain text, Thunderbird linkifies it like plain text. (For this option, choose: View – Message Body As – Plain Text.)

Suppressing automatically-generated links

It is possible to take some steps to suppress automatically-generated links, but you cannot completely suppress them.

Sending messages

When you write an HTML message, you can suppress automatically-generated links. Select the text that Thunderbird normally linkifies. Choose Insert – HTML... In the HTML editor, type anchor tags around the text. For example, if you type this but you do not want Thunderbird to linkify it:

In the HTML editor, change it to:


If there is already an anchor tag with attributes (class and href, typically), then remove the attributes to leave the tag looking like the example above.

Note:  People who receive your message might still see a link, if they use mail clients that linkify when they display messages. For example, Thunderbird users will probably see a link if they choose: View – Message Body As – Plain Text

Reading messages

When you read a plain text message, you cannot prevent Thunderbird from linkifying it. But you can change the appearance of the links so that they are not so obvious. In your userContent.css file, add:

.moz-text-flowed :link, .moz-text-plain :link {
  color: inherit !important;
  text-decoration: inherit !important;
  cursor: inherit !important;

See also