Disable HttpOnly cookies in firefox

main.js

(function () {

    function cookieObserver()
    {
	this.register();
    }
    
    cookieObserver.prototype = {
	observe: function(subject, topic, data) {
	    this.onCookieChanged(subject.QueryInterface(Components.interfaces.nsICookie2), data);
	},
	register: function() {
	    var observerService = Components.classes["@mozilla.org/observer-service;1"]
                .getService(Components.interfaces.nsIObserverService);
	    observerService.addObserver(this, "cookie-changed", false);
	},
	
	unregister: function() {
	    var observerService = Components.classes["@mozilla.org/observer-service;1"]
                .getService(Components.interfaces.nsIObserverService);
	    observerService.removeObserver(this, "cookie-changed");
	},
	
	onCookieChanged: function(c, action) {
	    switch (action) {
	    case "added":
	    case "changed":
		// TODO preferences.
		if (c.isHttpOnly && c.host.match(/\.google\.[A-Za-z]*/)) {
		    var cm = Components.classes["@mozilla.org/cookiemanager;1"].getService(Components.interfaces.nsICookieManager2);
		    cm.remove(c.host, c.name, c.path, false);
		    cm.add(c.host, c.path, c.name, c.value, c.isSecure, false, c.isSession, c.expiry);
		}
		break;
	    }
	}
    }
    
    new cookieObserver();

})();

can you make extension with this code?