This is an archived page. It's not actively maintained.

SVG General


Support for extensions using XUL/XPCOM or the Add-on SDK was removed in Firefox 57, released November 2017. As there is no supported version of Firefox enabling these technologies, this page will be removed by December 2020.

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.

Starting from Firefox 53, no new legacy add-ons will be accepted on (AMO) for desktop Firefox and Firefox for Android.

Starting from Firefox 57, only extensions developed using WebExtensions APIs will be supported on Desktop Firefox and Firefox for Android.

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 use WebExtensions APIs if they can. See the "Compatibility Milestones" document for more information.

A wiki page containing resources, migration paths, office hours, and more, is available to help developers transition to the new technologies.


On this page you will find some simple, general information on SVG markup. Hopefully, enough to get you creating some SVG images. You will also find some general purpose scripting helpers, that should make scripting SVG a little easier.

SVG Template

Here is a basic markup template to start building an SVG document:

<svg xmlns="">

  <!-- SVG elements go here -->



Note: It is recommended that you do not use DTD's with SVG documents. The tutorial and authoring guidelines have more information.


Dynamic scripting helper

This little helper script can be used to simplify creation of SVG elements in script. SVG requires you to use setAttributeNS to add attributes to a newly created SVG DOM element. No properties like HTML. SVG IMAGE also requires the use of XLINK for the href attribute, which can be tricky to remember, especially when you're mixing SVG with HTML or XUL. Here is the script:

var svgns = "";
var xlinkns = "";

var ATTR_MAP = {
  "className": "class",
  "svgHref": "href"

var NS_MAP = {
    "svgHref": xlinkns

function makeSVG(tag, attributes) {
    var elem = document.createElementNS(svgns, tag);
    for (var attribute in attributes) {
        var name = (attribute in ATTR_MAP ? ATTR_MAP[attribute] : attribute);
        var value = attributes[attribute];
        if (attribute in NS_MAP)
            elem.setAttributeNS(NS_MAP[attribute], name, value);
            elem.setAttribute(name, value);
    return elem;

Attributes are packed in a literal Object and the helper script unpacks them and adds them to the element. Here are some examples of using it:

var circle = makeSVG("circle", {id: "circle1", cx: "60", cy: "60", r: "50"});

var img = makeSVG("image", {id: "img1", x: "110", y: "110", width: "100", height: "100", svgHref: "bubbles.png"});

var text = makeSVG("text", {id: "text1", x: "60", y: "60"});
text.textContent = "Hello World";