fix replace function

assets/js/sections/qso.js

@@ -1078,7 +1078,7 @@ $("#callsign").keyup(function () {
 });
 
 RegExp.escape = function (text) {
-	return text.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&");
+	return String(text).replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&");
 }
 
 
@@ -1390,4 +1390,4 @@ $(document).ready(function () {
 
 	// everything loaded and ready 2 go
 	bc.postMessage('ready');
-});
+});