diff --git a/templates/index.html b/templates/index.html
index 69f02ef..1662dd1 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -261,6 +261,9 @@
 
 	function shareOnFediverse(questionId, contentToShare) {
 		const instanceDomain = document.getElementById(`fediInstance`).value.trim();
+		if (!instanceDomain) {
+			return;
+		}
 		const shareUrl = `https://${instanceDomain}/share?text=${contentToShare}`;
 
 		window.open(shareUrl, '_blank');