@font-face allows authors to specify online fonts to display text on their web pages. By allowing authors to provide their own fonts, @font-face eliminates the need to depend on the limited number of fonts users have installed on their computers.
In this example, the user’s local copy of “Helvetica Neue Bold” is used; if the user doesn’t have that font installed (two different names are tried), then the downloadable font named “MgOpenModernaBold.ttf” is used instead:
In Gecko, web fonts are subject to the same domain restriction (font files must be on the same domain as the page using them), unless HTTP access controls are used to relax this restriction.
Note: Because there are no defined MIME types for TrueType, OpenType, and WOFF fonts, the MIME type of the file specified is not considered.
When Gecko displays a page that uses web fonts, it initially displays text using the best CSS fallback font available on the user’s computer while it waits for the web font to finish downloading. As each web font finishes downloading, Gecko updates the text that uses that font. This lets the user to read the text on the page more quickly.