The `symbiont` module exports the `Symbiont` trait, which is used in the internal implementation of SDK modules, such as [`panel`](modules/sdk/panel.html) and [`page-worker`](modules/sdk/page-mod.html), that can load web content and attach [content scripts](dev-guide/guides/content-scripts/index.html) to it. A `Symbiont` loads the specified `contentURL` and content scripts into a frame, and sets up an asynchronous channel between the content scripts and the add-on code, enabling them to exchange messages using the [`port`](dev-guide/guides/content-scripts/using-port.html) or [`postMessage`](dev-guide/guides/content-scripts/using-postmessage.html) APIs. You map optionally pass a frame into the `Symbiont`'s constructor: if you don't, then a new hidden frame will be created to host the content. This trait is composed from the [`Loader`](modules/sdk/content/loader.html) and [`Worker`](modules/sdk/content/worker.html) traits. It inherits functions to load and configure content scripts from the `Loader`, and functions to exchange messages between content scripts and the main add-on code from the `Worker`. var { Symbiont } = require('sdk/content/content'); var Thing = Symbiont.resolve({ constructor: '_init' }).compose({ constructor: function Thing(options) { // `getMyFrame` returns the host application frame in which // the page is loaded. this._frame = getMyFrame(); this._init(options) } }); See the [panel][] module for a real-world example of usage of this module. [panel]:modules/sdk/panel.html @class Symbiont is composed from the [Worker][] trait, therefore instances of Symbiont and their descendants expose all the public properties exposed by [Worker][] along with additional public properties that are listed below: [Worker]:modules/sdk/content/worker.html @constructor Creates a content symbiont. @param options {object} Options for the constructor. Includes all the keys that the [Worker](modules/sdk/content/worker.html) constructor accepts and a few more: @prop [frame] {object} The host application frame in which the page is loaded. If frame is not provided hidden one will be created. @prop [contentScriptWhen="end"] {string} When to load the content scripts. This may take one of the following values: * "start": load content scripts immediately after the document element for the page is inserted into the DOM, but before the DOM content itself has been loaded * "ready": load content scripts once DOM content has been loaded, corresponding to the [DOMContentLoaded](https://developer.mozilla.org/en/Gecko-Specific_DOM_Events) event * "end": load content scripts once all the content (DOM, JS, CSS, images) for the page has been loaded, at the time the [window.onload event](https://developer.mozilla.org/en/DOM/window.onload) fires This property is optional and defaults to "end". @prop [contentScriptOptions] {object} Read-only value exposed to content scripts under `self.options` property. Any kind of jsonable value (object, array, string, etc.) can be used here. Optional. @prop [allow] {object} Permissions for the content, with the following keys: @prop [script] {boolean} Whether or not to execute script in the content. Defaults to true. Optional. Optional. @property {array} The local file URLs of content scripts to load. Content scripts specified by this property are loaded *before* those specified by the `contentScript` property. @property {array} The texts of content scripts to load. Content scripts specified by this property are loaded *after* those specified by the `contentScriptFile` property. @property {string} When to load the content scripts. This may have one of the following values: * "start": load content scripts immediately after the document element for the page is inserted into the DOM, but before the DOM content itself has been loaded * "ready": load content scripts once DOM content has been loaded, corresponding to the [DOMContentLoaded](https://developer.mozilla.org/en/Gecko-Specific_DOM_Events) event * "end": load content scripts once all the content (DOM, JS, CSS, images) for the page has been loaded, at the time the [window.onload event](https://developer.mozilla.org/en/DOM/window.onload) fires @property {object} Read-only value exposed to content scripts under `self.options` property. Any kind of jsonable value (object, array, string, etc.) can be used here. Optional. @property {string} The URL of the content loaded. @property {object} Permissions for the content, with a single boolean key called `script` which defaults to true and indicates whether or not to execute scripts in the content.