changed xpath and observer to work with two-column table

jwconfsignal.js

@@ -24,7 +24,7 @@ JWConfZoomHand
 	var JWConfRaisings = 0;
 
 	// loop through table of attendees and call for observer subscription
-	function subscribeNewAttendees() {
+/* 	function subscribeNewAttendees() {
 		if (signalEnabled === false) {
 			return;
 		}
@@ -35,10 +35,39 @@ JWConfZoomHand
 					addObserver(row);
 			}
 		}
+	} */
+	
+	function subscribeNewAttendees() {
+		if (signalEnabled === false) {
+			return;
+		}
+		var tablesAttendees = document.evaluate('//table[starts-with(@class,"listener-table")]', document, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null );
+		var tableAttendees = null;
+		for ( var i=0; i < tablesAttendees.snapshotLength; i++ )
+		{
+			tableAttendees = tablesAttendees.snapshotItem(i)
+			for (var i = 0, row; row = tableAttendees.rows[i]; i++) {
+				if (row.parentNode.localName !== "thead") {
+					addObserver(row);
+				}
+			}  
+		}
 	}
 	
+/* 	
+    wegen unten XPathResult.ORDERED_NODE_ITERATOR_TYPE durch XPathResult.ORDERED_NODE_SNAPSHOT_TYPE ersetzt (
+	
+	siehe https://developer.mozilla.org/en-US/docs/Web/API/Document/evaluate
+  	    Results of NODE_SNAPSHOT types are snapshots, which are essentially lists of matched nodes. You can make changes to the document by altering snapshot nodes. Modifying the document doesn't invalidate the snapshot; however, if the document is changed, the snapshot may not correspond to the current state of the document, since nodes may have moved, been changed, added, or removed.
+
+    führt leider manchmal zu
+	jwconfsignal.js:46 Uncaught DOMException: Failed to execute 'iterateNext' on 'XPathResult': The document has mutated since the result was returned.
+    at subscribeNewAttendees (chrome-extension://hhcadpapjmemfpokloljohmahipbjhmb/jwconfsignal.js:46:42)
+    at chrome-extension://hhcadpapjmemfpokloljohmahipbjhmb/jwconfsignal.js:250:4 */
+	
 	function updateJWConfRaisings() {
-		JWConfRaisings = document.evaluate('count(//table[@class="listener-table"]//tr[@class="detected speechrequest"])', document, null, XPathResult.ANY_TYPE, null ).numberValue;
+		//JWConfRaisings = document.evaluate('count(//table[starts-with(@class,"listener-table")]//tr[@class="speechrequest detected"])', document, null, XPathResult.ANY_TYPE, null ).numberValue;
+		JWConfRaisings = document.evaluate('count(//table[starts-with(@class,"listener-table")]//tr[@class="detected speechrequest" or @class="speechrequest detected" or @style="background-color: rgb(23, 121, 186); color: rgb(254, 254, 254);" or @style="background-color: rgb(161, 184, 105); color: rgb(254, 254, 254);"])', document, null, XPathResult.ANY_TYPE, null ).numberValue;
 	}
 	
 	function subscribeAttList() {