diff --git a/packages/app-cli/tests/support/plugins/content_script/src/index.ts b/packages/app-cli/tests/support/plugins/content_script/src/index.ts
index c7ed3d092..1fb7038fb 100644
--- a/packages/app-cli/tests/support/plugins/content_script/src/index.ts
+++ b/packages/app-cli/tests/support/plugins/content_script/src/index.ts
@@ -3,6 +3,22 @@ import { ContentScriptType } from 'api/types';
 
 joplin.plugins.register({
 	onStart: async function() {
+		await joplin.commands.register({
+			name: 'testCommand',
+			label: 'My Test Command',
+			execute: async (...args) => {
+				alert('Got command "testCommand" with args: ' + JSON.stringify(args));
+			},
+		});
+
+		await joplin.commands.register({
+			name: 'testCommandNoArgs',
+			label: 'My Test Command (no args)',
+			execute: async () => {
+				alert('Got command "testCommandNoArgs"');
+			},
+		});
+
 		await joplin.plugins.registerContentScript(
 			ContentScriptType.MarkdownItPlugin,
 			'justtesting',
diff --git a/packages/app-cli/tests/support/plugins/content_script/src/markdownItTestPlugin.css b/packages/app-cli/tests/support/plugins/content_script/src/markdownItTestPlugin.css
index a168fce07..dcfc4e668 100644
--- a/packages/app-cli/tests/support/plugins/content_script/src/markdownItTestPlugin.css
+++ b/packages/app-cli/tests/support/plugins/content_script/src/markdownItTestPlugin.css
@@ -1,4 +1,9 @@
 .just-testing {
-	background-color: red;
-	color: yellow;
+	background-color: rgb(202, 255, 255);
+	color: rgb(82, 0, 78);
+}
+
+.just-testing a {
+	background-color: rgb(202, 255, 255);
+	color: rgb(10, 0, 104);
 }
\ No newline at end of file
diff --git a/packages/app-cli/tests/support/plugins/content_script/src/markdownItTestPlugin.js b/packages/app-cli/tests/support/plugins/content_script/src/markdownItTestPlugin.js
index a294bfb25..63520367e 100644
--- a/packages/app-cli/tests/support/plugins/content_script/src/markdownItTestPlugin.js
+++ b/packages/app-cli/tests/support/plugins/content_script/src/markdownItTestPlugin.js
@@ -6,7 +6,13 @@ function plugin(markdownIt, _options) {
 	markdownIt.renderer.rules.fence = function(tokens, idx, options, env, self) {
 		const token = tokens[idx];
 		if (token.info !== 'justtesting') return defaultRender(tokens, idx, options, env, self);
-		return `<div class="just-testing">JUST TESTING: ${token.content}</div>`;
+		return `
+			<div class="just-testing">
+				<p>JUST TESTING: ${token.content}</p>
+				<p><a href="#" onclick="webviewApi.executeCommand('testCommand', 'one', 'two'); return false;">Click to send "testCommand" to plugin</a></p>
+				<p><a href="#" onclick="webviewApi.executeCommand('testCommandNoArgs'); return false;">Click to send "testCommandNoArgs" to plugin</a></p>
+			</div>
+		`;
 	};
 }
 
diff --git a/packages/app-desktop/gui/NoteEditor/utils/useMessageHandler.ts b/packages/app-desktop/gui/NoteEditor/utils/useMessageHandler.ts
index f305b94fa..abca8e5f8 100644
--- a/packages/app-desktop/gui/NoteEditor/utils/useMessageHandler.ts
+++ b/packages/app-desktop/gui/NoteEditor/utils/useMessageHandler.ts
@@ -3,6 +3,7 @@ import { FormNote } from './types';
 import contextMenu from './contextMenu';
 import ResourceEditWatcher from '@joplin/lib/services/ResourceEditWatcher/index';
 import { _ } from '@joplin/lib/locale';
+import CommandService from '@joplin/lib/services/CommandService';
 const BaseItem = require('@joplin/lib/models/BaseItem');
 const BaseModel = require('@joplin/lib/BaseModel').default;
 const Resource = require('@joplin/lib/models/Resource.js');
@@ -90,6 +91,10 @@ export default function useMessageHandler(scrollWhenReady: any, setScrollWhenRea
 			}
 		} else if (msg.indexOf('#') === 0) {
 			// This is an internal anchor, which is handled by the WebView so skip this case
+		} else if (msg === 'contentScriptExecuteCommand') {
+			const commandName = arg0.name;
+			const commandArgs = arg0.args || [];
+			void CommandService.instance().execute(commandName, ...commandArgs);
 		} else {
 			bridge().showErrorMessageBox(_('Unsupported link or message: %s', msg));
 		}
diff --git a/packages/app-desktop/gui/note-viewer/index.html b/packages/app-desktop/gui/note-viewer/index.html
index 5a0dbe00c..e7cd582c3 100644
--- a/packages/app-desktop/gui/note-viewer/index.html
+++ b/packages/app-desktop/gui/note-viewer/index.html
@@ -49,10 +49,24 @@
 	<script src="./lib.js"></script>
 
 	<script>
+	// This is function used internally to send message from the webview to
+	// the host.
 	const ipcProxySendToHost = (methodName, arg) => {
 		window.postMessage({ target: 'main', name: methodName, args: [ arg ] }, '*');
 	}
 
+	// This function is reserved for plugin, currently only to allow
+	// executing a command, but more features could be added to the object
+	// later on.
+	const webviewApi = {
+		executeCommand: function (commandName, ...args) {
+			return ipcProxySendToHost('contentScriptExecuteCommand', {
+				name: commandName,
+				args: args,	
+			});
+		}
+	}
+
 	let pluginAssetsAdded_ = {};
 
 	try {
diff --git a/packages/lib/services/plugins/api/JoplinPlugins.ts b/packages/lib/services/plugins/api/JoplinPlugins.ts
index bca52124e..af0cbee13 100644
--- a/packages/lib/services/plugins/api/JoplinPlugins.ts
+++ b/packages/lib/services/plugins/api/JoplinPlugins.ts
@@ -51,14 +51,20 @@ export default class JoplinPlugins {
 	}
 
 	/**
-	 * Registers a new content script. Unlike regular plugin code, which runs in a separate process, content scripts run within the main process code
-	 * and thus allow improved performances and more customisations in specific cases. It can be used for example to load a Markdown or editor plugin.
+	 * Registers a new content script. Unlike regular plugin code, which
+	 * runs in a separate process, content scripts run within the main
+	 * process code and thus allow improved performances and more
+	 * customisations in specific cases. It can be used for example to load
+	 * a Markdown or editor plugin.
 	 *
-	 * Note that registering a content script in itself will do nothing - it will only be loaded in specific cases by the relevant app modules
-	 * (eg. the Markdown renderer or the code editor). So it is not a way to inject and run arbitrary code in the app, which for safety and performance reasons is not supported.
+	 * Note that registering a content script in itself will do nothing -
+	 * it will only be loaded in specific cases by the relevant app modules
+	 * (eg. the Markdown renderer or the code editor). So it is not a way
+	 * to inject and run arbitrary code in the app, which for safety and
+	 * performance reasons is not supported.
 	 *
-	 * [View the renderer demo plugin](https://github.com/laurent22/joplin/tree/dev/packages/app-cli/tests/support/plugins/content_script)
-	 * [View the editor demo plugin](https://github.com/laurent22/joplin/tree/dev/packages/app-cli/tests/support/plugins/codemirror_content_script)
+	 * * [View the renderer demo plugin](https://github.com/laurent22/joplin/tree/dev/packages/app-cli/tests/support/plugins/content_script)
+	 * * [View the editor demo plugin](https://github.com/laurent22/joplin/tree/dev/packages/app-cli/tests/support/plugins/codemirror_content_script)
 	 *
 	 * @param type Defines how the script will be used. See the type definition for more information about each supported type.
 	 * @param id A unique ID for the content script.
diff --git a/packages/lib/services/plugins/api/types.ts b/packages/lib/services/plugins/api/types.ts
index 661464b4d..a4e18953f 100644
--- a/packages/lib/services/plugins/api/types.ts
+++ b/packages/lib/services/plugins/api/types.ts
@@ -334,7 +334,8 @@ export type Path = string[];
 
 export enum ContentScriptType {
 	/**
-	 * Registers a new Markdown-It plugin, which should follow the template below.
+	 * Registers a new Markdown-It plugin, which should follow the template
+	 * below.
 	 *
 	 * ```javascript
 	 * module.exports = {
@@ -350,14 +351,49 @@ export enum ContentScriptType {
 	 *     }
 	 * }
 	 * ```
+	 * See [the
+	 * demo](https://github.com/laurent22/joplin/tree/dev/packages/app-cli/tests/support/plugins/content_script)
+	 * for a simple Markdown-it plugin example.
 	 *
-	 * - The `context` argument is currently unused but could be used later on to provide access to your own plugin so that the content script and plugin can communicate.
+	 * ## Exported members
 	 *
-	 * - The **required** `plugin` key is the actual Markdown-It plugin - check the [official doc](https://github.com/markdown-it/markdown-it) for more information. The `options` parameter is of type [RuleOptions](https://github.com/laurent22/joplin/blob/dev/packages/renderer/MdToHtml.ts), which contains a number of options, mostly useful for Joplin's internal code.
+	 * - The `context` argument is currently unused but could be used later
+	 *   on to provide access to your own plugin so that the content script
+	 *   and plugin can communicate.
 	 *
-	 * - Using the **optional** `assets` key you may specify assets such as JS or CSS that should be loaded in the rendered HTML document. Check for example the Joplin [Mermaid plugin](https://github.com/laurent22/joplin/blob/dev/packages/renderer/MdToHtml/rules/mermaid.ts) to see how the data should be structured.
+	 * - The **required** `plugin` key is the actual Markdown-It plugin -
+	 *   check the [official
+	 *   doc](https://github.com/markdown-it/markdown-it) for more
+	 *   information. The `options` parameter is of type
+	 *   [RuleOptions](https://github.com/laurent22/joplin/blob/dev/packages/renderer/MdToHtml.ts),
+	 *   which contains a number of options, mostly useful for Joplin's
+	 *   internal code.
 	 *
-	 * To include a regular Markdown-It plugin, that doesn't make use of any Joplin-specific features, you would simply create a file such as this:
+	 * - Using the **optional** `assets` key you may specify assets such as
+	 *   JS or CSS that should be loaded in the rendered HTML document.
+	 *   Check for example the Joplin [Mermaid
+	 *   plugin](https://github.com/laurent22/joplin/blob/dev/packages/renderer/MdToHtml/rules/mermaid.ts)
+	 *   to see how the data should be structured.
+	 *
+	 * ## Passing messages from the content script to your plugin
+	 *
+	 * The application provides the following function to allow executing
+	 * commands from the rendered HTML code:
+	 *
+	 * `webviewApi.executeCommand(commandName, ...args)`
+	 *
+	 * So you can use this mechanism to pass messages from the note viewer
+	 * to your own plugin. To do so you would define a command, using
+	 * `joplin.commands.register`, then you would call this command using
+	 * the `webviewApi` object. See again [the
+	 * demo](https://github.com/laurent22/joplin/tree/dev/packages/app-cli/tests/support/plugins/content_script)
+	 * to see how this can be done.
+	 *
+	 * ## Registering an existing Markdown-it plugin
+	 *
+	 * To include a regular Markdown-It plugin, that doesn't make use of
+	 * any Joplin-specific features, you would simply create a file such as
+	 * this:
 	 *
 	 * ```javascript
 	 * module.exports = {
@@ -371,7 +407,8 @@ export enum ContentScriptType {
 	 */
 	MarkdownItPlugin = 'markdownItPlugin',
 	/**
-	 * Registers a new CodeMirror plugin, which should follow the template below.
+	 * Registers a new CodeMirror plugin, which should follow the template
+	 * below.
 	 *
 	 * ```javascript
 	 * module.exports = {
@@ -382,8 +419,8 @@ export enum ContentScriptType {
 	 *             },
 	 *             codeMirrorResources: [],
 	 *             codeMirrorOptions: {
-	 *									// ...
-	 *						 },
+	 *                                  // ...
+	 *                       },
 	 *             assets: {
 	 *                 // ...
 	 *             },
@@ -392,19 +429,42 @@ export enum ContentScriptType {
 	 * }
 	 * ```
 	 *
-	 * - The `context` argument is currently unused but could be used later on to provide access to your own plugin so that the content script and plugin can communicate.
+	 * - The `context` argument is currently unused but could be used later
+	 *   on to provide access to your own plugin so that the content script
+	 *   and plugin can communicate.
 	 *
-	 * - The `plugin` key is your CodeMirror plugin. This is where you can register new commands with CodeMirror or interact with the CodeMirror instance as needed.
+	 * - The `plugin` key is your CodeMirror plugin. This is where you can
+	 *   register new commands with CodeMirror or interact with the
+	 *   CodeMirror instance as needed.
 	 *
-	 * - The `codeMirrorResources` key is an array of CodeMirror resources that will be loaded and attached to the CodeMirror module. These are made up of addons, keymaps, and modes. For example, for a plugin that want's to enable clojure highlighting in code blocks. `codeMirrorResources` would be set to `['mode/clojure/clojure']`.
+	 * - The `codeMirrorResources` key is an array of CodeMirror resources
+	 *   that will be loaded and attached to the CodeMirror module. These
+	 *   are made up of addons, keymaps, and modes. For example, for a
+	 *   plugin that want's to enable clojure highlighting in code blocks.
+	 *   `codeMirrorResources` would be set to `['mode/clojure/clojure']`.
 	 *
-	 * - The `codeMirrorOptions` key contains all the [CodeMirror](https://codemirror.net/doc/manual.html#config) options that will be set or changed by this plugin. New options can alse be declared via [`CodeMirror.defineOption`](https://codemirror.net/doc/manual.html#defineOption), and then have their value set here. For example, a plugin that enables line numbers would set `codeMirrorOptions` to `{'lineNumbers': true}`.
+	 * - The `codeMirrorOptions` key contains all the
+	 *   [CodeMirror](https://codemirror.net/doc/manual.html#config)
+	 *   options that will be set or changed by this plugin. New options
+	 *   can alse be declared via
+	 *   [`CodeMirror.defineOption`](https://codemirror.net/doc/manual.html#defineOption),
+	 *   and then have their value set here. For example, a plugin that
+	 *   enables line numbers would set `codeMirrorOptions` to
+	 *   `{'lineNumbers': true}`.
 	 *
-	 * - Using the **optional** `assets` key you may specify **only** CSS assets that should be loaded in the rendered HTML document. Check for example the Joplin [Mermaid plugin](https://github.com/laurent22/joplin/blob/dev/packages/renderer/MdToHtml/rules/mermaid.ts) to see how the data should be structured.
+	 * - Using the **optional** `assets` key you may specify **only** CSS
+	 *   assets that should be loaded in the rendered HTML document. Check
+	 *   for example the Joplin [Mermaid
+	 *   plugin](https://github.com/laurent22/joplin/blob/dev/packages/renderer/MdToHtml/rules/mermaid.ts)
+	 *   to see how the data should be structured.
 	 *
-	 * One of the `plugin`, `codeMirrorResources`, or `codeMirrorOptions` keys must be provided for the plugin to be valid. Having multiple or all provided is also okay.
+	 * One of the `plugin`, `codeMirrorResources`, or `codeMirrorOptions`
+	 * keys must be provided for the plugin to be valid. Having multiple or
+	 * all provided is also okay.
 	 *
-	 * See the [demo plugin](https://github.com/laurent22/joplin/tree/dev/packages/app-cli/tests/support/plugins/codemirror_content_script) for an example of all these keys being used in one plugin.
+	 * See the [demo
+	 * plugin](https://github.com/laurent22/joplin/tree/dev/packages/app-cli/tests/support/plugins/codemirror_content_script)
+	 * for an example of all these keys being used in one plugin.
 	 */
 	CodeMirrorPlugin = 'codeMirrorPlugin',
 }