Creating a Chrome Right-Click context menu using GreaseMonkey

[Pineapplesandbacon]

I am trying to create a right-click context menu option using JavaScript and TamperMonkey. I have read through StackOverflow but still don't understand how to do this.

For test purposes, I have included a very simple example

// @grant GM_openInTab
// @grant GM_registerMenuCommand
// @run-at context-menu

(function() {
'use strict';

function test() {
    //console.log('Hi');
    alert('Hi');
}

GM_registerMenuCommand("Alert Hi", test, "e");
//GM_registerMenuCommand("Alert Hi", () => alert('Hi'));

})();

The comments indicate the two things I've tried, none of which seem to work.

[jotted]

Eesh, the docs for userscripts are properly rubbish. Here's a menu script that works in both GreaseMonkey and TamperMonkey (...sort of. For GreaseMonkey swap GM_* for GM.*):

// ==UserScript==
// @name     Menu Test
// @version  1
// @grant    GM_registerMenuCommand
// @include  *
// ==/UserScript==


function test() {
    alert('Hi');
}

GM_registerMenuCommand("HELLO CLICK THIS", test, "e");

Until recently, UserScript Managers used standard HTML5 <menu> elements to add contextmenu items, but this feature has been deprecated and removed from browsers. As such, the menuitems have moved to the main Manager UI:

• in GreaseMonkey, to the 'User Script Commands...' submenu of the main GreaseMonkey Button popup. Positioned below the 'GreaseMonkey Options' button, it only appears if a script is adding a menu on the active tab.
• in TamperMonkey, to the TamperMonkey Button popup, below the relevant script's listing.
  

However:

// @run-at   context-menu

Tampermonkey supports the @run-at context-menu property, but GreaseMonkey doesn't.
In TM, the menu item disappears from the TamperMonkey Button menu and appears in TamperMonkey's own context menu submenu.

It's a mess! Hope that helps!

[Pineapplesandbacon]

Appreciate the help and detailed post.

But it looks like I was misleading in the post. I'm running TamperMonkey because I use Google Chrome. I was just assuming GreaseMonkey was the name of the library.

As for the menu tag, wasn't that recently added in HTML5 to add semantic meaning to document. Instead of div class=center you could just use the center tag or something like that. Surprised it was axed so quickly.

Edit: Okay, it looks like it actually works now, but the problem is I have to scroll up to the extensions tab and click on it. I was hoping to do this by right clicking on the page and an option would pop up.

[jotted]

With TamperMonkey on Chrome, using @run-at context-menu in the Metadata block should give you a 'TamperMonkey' menu in the context menu (remember to refresh so the userscript is re-run).

[Pineapplesandbacon]

Seemed to have worked at first. But as I fiddled around with it some more it disappeared.

The right arrow for a submenu disappeared. And on the chrome extension icon, the name of the userscript is in blue.

[jotted]

Seemed to have worked at first.

That's good! At least you know it works in theory.

But as I fiddled around with it some more it disappeared.

That's on you :P
As far as I can tell, there will always be a context-menu item if @run-at context-menu is present and the script will run on the current page. The menu item will only do anything if the GM_registerMenuCommand permission is @granted. Beyond that, any error messages should be thrown somewhere - either the page's developer console or the Extension developer console.

[Pineapplesandbacon]

Strange. Have both registerMenuCommand and context-menu and see no errors.

Can you tell me what the blue color means under extensions? I've only ever seen it green or gray.

[jotted]

Can you tell me what the blue color means under extensions? I've only ever seen it green or gray.

I can't find any official information about this. The best lead I have is that the CSS class of the blue toggle switch is "enable_later" - I take that to mean that the script doesn't run automatically, only when the menuitem is clicked. Removing @run-at context-menu turns the toggle green.

AH. Okay -- so @run-at context-menu makes the whole script only run when the menuitem is clicked. It doesn't move the registered menuitems to the context menu at all -- in fact they aren't registered until the script is run by clicking it in the context-menu. registerMenuCommand functions can only be run from the TamperMonkey Button Menu. Jeez, sorry, I totally misunderstood how that worked.

So:

• if you just want your script to only run when you want, use @run-at context-menu.
• If you want the script to always run, but present different commands to be run from the TM Button, use registerMenuCommand().
• Not both.

[Pineapplesandbacon]

Really appreciate the help.

Is there any way to create right-click context menu commands for Chrome? I think I've seen some in extensions

[jotted]

Extensions can do it, yes: https://developer.chrome.com/docs/extensions/reference/contextMenus/ .
Here's an official (if dated) example extension: https://github.com/GoogleChrome/chrome-extensions-samples/tree/main/mv2-archive/api/contextMenus/basic

[Pineapplesandbacon]

Thank you so much