fix injection in firefox

.config/qutebrowser/greasemonkey/onlinetichu.js

@@ -1,16 +1,18 @@
 // ==UserScript==
 // @name         onlinetichu.com card counter
-// @version      1.0.0
+// @version      1.0.2
 // @description  automatically count cards at onlinetichu.com
 // @author       kesslermaximilian
 // @match        *://*.onlinetichu.com/Site/Game/Table/*
 // ==/UserScript==
 
 // disable auto fold functionality completely
+function injectCounter() {
   if (ot.AutoFold) {
     ot.$autoFold.click()
     ot.$autoFold.hide()
   }
+
   var myStyles = `
     #playedHigh {
       position: absolute;
@@ -250,6 +252,8 @@ if (!window.otc) {
     window.otc = OnlineTichuCounter;
   }
 
+  otc.$showRemaining.hide();
+
   // add functionality to smartFold button
   otc.$smartFold.click(function () {
     otc.smartFold = !otc.smartFold;
@@ -397,3 +401,21 @@ MyReviewExchange = (function() {
   ot.reaction.TableState = MyTableState;
   ot.reaction.Chat = MyChat;
   ot.action.ExchangeCards = MyExchangeCards;
+};
+
+
+// Special care is to be taken to safely inject our javascript into the websiet
+// without the website being able to talk back to greasemonkey
+// (which would be a security problem)
+// see
+// https://stackoverflow.com/questions/5006460/userscripts-greasemonkey-calling-a-websites-javascript-functions
+// and the excellent answer by Wayne for details on this
+function exec(fn) {
+    var script = document.createElement('script');
+    script.setAttribute("type", "application/javascript");
+    script.textContent = '(' + fn + ')();';
+    document.body.appendChild(script); // run the script
+    document.body.removeChild(script); // clean up
+}
+
+exec(injectCounter);