diff --git a/pinback.js b/pinback.js
index 6d90549..a98b544 100644
--- a/pinback.js
+++ b/pinback.js
@@ -174,7 +174,7 @@
 
   // simple escape html
   function escapeHtml(unsafe) {
-    return unsafe.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;").replace(/"/g, "&quot;").replace(/'/g, "&#039;");
+    return unsafe?.replace?.(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;").replace(/"/g, "&quot;").replace(/'/g, "&#039;") || "";
   }
 
   // generate Netscape bookmark file