Get Firefox to run XUL type script on startup

Question

With Firefox 17.0.1 I am using an add-on called KeyConfig 20110522 to set some new hot keys and also set the acceltext of menuitems for my new keys as well as for add-ons that do not bother to do so.

I want the acceltext of the menuitems to be set when Firefox starts, but currently I am just using a hot key to execute the following code against the UI via KeyConfig:

document.getElementById("tabmix-menu")
  .setAttribute("acceltext","Alt+Ctrl+Shift+T");
// more of the same...

I need a couple of beginners tips:

How can I execute arbitrary code against the UI in the same way as I execute against an HTML page via the console?
Is there a sneaky way to get a clump of code to execute on browser start-up without delving into XUL development?
Is there a way to trace commands executed against the UI so I can get at command calls instead of using triggers when I set my hot keys like so:

document.getElementById("tabmix-menu").click();

Any other tips on this type of low-level hacking would also be welcome.

score 0 · Answer 1 · edited Sep 11 '16 at 23:30

You can execute arbitrary code against the Firefox UI from an addon, but as you say, doing all the XUL related stuff is a bit boring :-)

Enter "Bootstrapped" extensions!

Part 1:

A "Bootstrapped" (or re-startless) extension needs only an install.rdf file to identify the addon, and a bootstrap.js file to implement the bootstrap interface.

Bootstrapped Extension: https://developer.mozilla.org/en-US/docs/Extensions/Bootstrapped_extensions
Good example: http://blog.fpmurphy.com/2011/02/firefox-4-restartless-add-ons.html

The bootstrap interface can be implemented very simply:

function install() {}
function uninstall() {}
function shutdown(data, reason) {}
function startup(data, reason) { /* YOUR ARBITRARY CODE HERE! */ }

You compile the extension by putting install.rdf and bootstrap.js into the top-level of a new zip file, and rename the zip file extension to .xpi.

Part 2:

Your code is privileged and can use any of the Mozilla platform APIs. There is however an issue of timing. The moment-in-time at which the "startup" function is executed is one at which no Chrome window objects exist yet!

If it's important for your code that you have a Chrome Window, we need to wait for it to appear:

// useful services.
Cu.import("resource://gre/modules/Services.jsm");    
var loader = Cc["@mozilla.org/moz/jssubscript-loader;1"]
                .getService(Ci.mozIJSSubScriptLoader);

var wmSvc = Cc["@mozilla.org/appshell/window-mediator;1"]
                .getService(Ci.nsIWindowMediator);

var logSvc = Cc["@mozilla.org/consoleservice;1"]
                .getService(Ci.nsIConsoleService);

// get the first gBrowser 
var done_startup = 0;
var windowListener;
function do_startup(win) {

    if (done_startup) return;
    done_startup = 1;
    wmSvc.removeListener(windowListener);

    var browserEnum = wmSvc.getEnumerator("navigator:browser");
    var browserWin = browserEnum.getNext();
    var tabbrowser = browserWin.gBrowser;

    /* your code goes here! */
}

// window listener implementation
windowListener = {
    onWindowTitleChange: function(aWindow, aTitle) {},
    onCloseWindow:       function(aWindow) {},
    onOpenWindow:        function(aWindow) {
        var win = aWindow.QueryInterface(Ci.nsIInterfaceRequestor)
                     .getInterface(Ci.nsIDOMWindowInternal || Ci.nsIDOMWindow);
        win.addEventListener("load", function(aEvent) {
            win.removeEventListener("load", arguments.callee, false);
            if (aEvent.originalTarget.nodeName != "#document") return;
            do_startup();
        }
};

// CODE ENTRY POINT (put this in bootstrap "startup" function)
wmSvc.addListener(windowListener);

Get Firefox to run XUL type script on startup

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