Add-ons using the techniques described in this document are considered a legacy technology in Firefox. Don't use these techniques to develop new add-ons. Use WebExtensions instead. If you maintain an add-on which uses the techniques described here, consider migrating it to use WebExtensions.
From Firefox 53 onwards, no new legacy add-ons will be accepted on addons.mozilla.org (AMO).
From Firefox 57 onwards, WebExtensions will be the only supported extension type, and Firefox will not load other types.
Even before Firefox 57, changes coming up in the Firefox platform will break many legacy extensions. These changes include multiprocess Firefox (e10s), sandboxing, and multiple content processes. Legacy extensions that are affected by these changes should migrate to WebExtensions if they can. See the "Compatibility Milestones" document for more.
A wiki page containing resources, migration paths, office hours, and more, is available to help developers transition to the new technologies.
SVG is an XML based makeup language and can be embedded into other markup languages, like XHTML and XUL.
Embedding in XHTML
Make sure you use the right namespace when embedding. Notice the template and example use XHTML to handle the namespacing.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:svg="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink">
<body>
<!-- HTML and SVG go here -->
</body>
</html>
Example:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:svg="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink">
<body>
<p>hello</p>
<svg:svg version="1.1" baseProfile="full" width="150" height="150">
<svg:rect x="10" y="10" width="100" height="100" fill="red"/>
<svg:circle cx="50" cy="50" r="30" fill="blue"/>
</svg:svg>
<p>world</p>
</body>
</html>
Embedding into XUL
Make sure you use the right namespace when embedding
<?xml version="1.0"?>
<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
xmlns:svg="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink">
<!-- XUL and SVG go here -->
</window>
Example:
<?xml version="1.0"?>
<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
xmlns:svg="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink">
<vbox>
<label value="hello"/>
<svg:svg version="1.1" baseProfile="full" width="150" height="150">
<svg:rect x="10" y="10" width="100" height="100" fill="red"/>
<svg:circle cx="50" cy="50" r="30" fill="blue"/>
</svg:svg>
<label value="world"/>
</vbox>
</window>