diff --git a/connect/headers.go b/connect/headers.go
new file mode 100644
index 0000000000000000000000000000000000000000..b3ab18a018314d00b5ffe9aabad8943d959b1b6a
--- /dev/null
+++ b/connect/headers.go
@@ -0,0 +1,9 @@
+//go:build !js || !wasm
+
+package connect
+
+import "net/http"
+
+func (wc *webConn) addHeaders(header http.Header) http.Header {
+	return header
+}
diff --git a/connect/headers_js.go b/connect/headers_js.go
new file mode 100644
index 0000000000000000000000000000000000000000..17620bc905aec1c2f49c50ff375626c4745f297d
--- /dev/null
+++ b/connect/headers_js.go
@@ -0,0 +1,10 @@
+//go:build js && wasm
+
+package connect
+
+import "net/http"
+
+func (wc *webConn) addHeaders(header http.Header) http.Header {
+	req.Header.Add("js.fetch:mode", "no-cors")
+	return header
+}
diff --git a/connect/webConn.go b/connect/webConn.go
index 3f899829b1db63521757b29fb66c25c595306b2e..4eb69ce246bb919c8f1471a893b4fbe071e2a31e 100644
--- a/connect/webConn.go
+++ b/connect/webConn.go
@@ -191,10 +191,10 @@ func (wc *webConn) IsOnline() (time.Duration, bool) {
 	addr := wc.h.GetAddress()
 	pingTimeout := wc.h.params.PingTimeout
 
-	return isOnlineHelper(addr, pingTimeout)
+	return wc.isOnlineHelper(addr, pingTimeout)
 }
 
-func isOnlineHelper(addr string, pingTimeout time.Duration) (time.Duration, bool) {
+func (wc *webConn) isOnlineHelper(addr string, pingTimeout time.Duration) (time.Duration, bool) {
 	start := time.Now()
 	tr := &http.Transport{
 		TLSClientConfig: &tls.Config{
@@ -225,7 +225,7 @@ func isOnlineHelper(addr string, pingTimeout time.Duration) (time.Duration, bool
 	}
 
 	// IMPORTANT - enables better HTTP(S) discovery, because many browsers block CORS by default.
-	//req.Header.Add("js.fetch:mode", "no-cors")
+	req.Header = wc.addHeaders(req.Header)
 	jww.TRACE.Printf("(GO request): %+v", req)
 
 	req = req.WithContext(httptrace.WithClientTrace(req.Context(), trace))
diff --git a/connect/webConn_test.go b/connect/webConn_test.go
index 8bca386662a2710b8cb36e0dd35b3361c9fe0067..a84c92c08632898b037569dff07d4cbc21d933b7 100644
--- a/connect/webConn_test.go
+++ b/connect/webConn_test.go
@@ -145,6 +145,7 @@ func Test_checkErrorExceptions(t *testing.T) {
 
 //func Test_isOnline_actual(t *testing.T) {
 //	targetAddr := ".xxnode.io:22840"
-//	_, ok := isOnlineHelper(targetAddr, time.Second*10)
+//	wc := webConn{}
+//	_, ok := wc.isOnlineHelper(targetAddr, time.Second*10)
 //	t.Fatal(ok)
 //}