diff --git a/copyparty/web/browser.js b/copyparty/web/browser.js
index fc02f541..3243ce9a 100644
--- a/copyparty/web/browser.js
+++ b/copyparty/web/browser.js
@@ -1353,7 +1353,7 @@ function play(tid, is_ev, seek, call_depth) {
 				mp.au = mp.au_ogvjs = new OGVPlayer();
 			}
 			catch (ex) {
-				return toast.err(30, 'your browser cannot play ogg/vorbis/opus\n\n' + ex +
+				return toast.err(30, 'your browser cannot play ogg/vorbis/opus\n\n' + basenames(ex) +
 					'\n\n<a href="#" onclick="new OGVPlayer();">click here</a> for a full crash report');
 			}
 			attempt_play = is_ev;
@@ -1445,7 +1445,7 @@ function play(tid, is_ev, seek, call_depth) {
 		return true;
 	}
 	catch (ex) {
-		toast.err(0, esc('playback failed: ' + ex));
+		toast.err(0, esc('playback failed: ' + basenames(ex)));
 	}
 	setclass(oid, 'play');
 	setTimeout(next_song, 500);
@@ -1479,7 +1479,7 @@ function evau_error(e) {
 
 	err += '\n\nFile: «' + uricom_dec(eplaya.src.split('/').slice(-1)[0])[0] + '»';
 
-	toast.warn(15, esc(err + ''));
+	toast.warn(15, esc(basenames(err)));
 }
 
 
diff --git a/copyparty/web/up2k.js b/copyparty/web/up2k.js
index 6411c67f..b182b0f1 100644
--- a/copyparty/web/up2k.js
+++ b/copyparty/web/up2k.js
@@ -1953,7 +1953,7 @@ function up2k_init(subtle) {
                 flag = up2k_flagbus();
             }
             catch (ex) {
-                toast.err(5, "not supported on your browser:\n" + ex);
+                toast.err(5, "not supported on your browser:\n" + esc(basenames(ex)));
                 bcfg_set('flag_en', false);
             }
         }
diff --git a/copyparty/web/util.js b/copyparty/web/util.js
index 95e1c694..90af1717 100644
--- a/copyparty/web/util.js
+++ b/copyparty/web/util.js
@@ -29,18 +29,24 @@ function esc(txt) {
         }[c];
     });
 }
-window.onunhandledrejection = function (e) {
-    var err = e.reason;
-    try {
-        err += '\n' + e.reason.stack;
-    }
-    catch (e) { }
-    console.log("REJ: " + err);
-    try {
-        toast.warn(30, err);
-    }
-    catch (e) { }
-};
+function basenames(txt) {
+    return (txt + '').replace(/https?:\/\/[^ \/]+\//g, '/').replace(/js\?_=[a-zA-Z]{4}/g, 'js');
+}
+if ((document.location + '').indexOf(',rej,') + 1)
+    window.onunhandledrejection = function (e) {
+        var err = e.reason;
+        try {
+            err += '\n' + e.reason.stack;
+        }
+        catch (e) { }
+        err = basenames(err);
+        console.log("REJ: " + err);
+        try {
+            toast.warn(30, err);
+        }
+        catch (e) { }
+    };
+
 try {
     console.hist = [];
     var hook = function (t) {
@@ -151,7 +157,7 @@ function vis_exh(msg, url, lineNo, columnNo, error) {
             );
             document.head.appendChild(s);
         }
-        exbox.innerHTML = html.join('\n').replace(/https?:\/\/[^ \/]+\//g, '/').replace(/js\?_=[a-zA-Z]{4}/g, 'js').replace(/<ghi>/, 'https://github.com/9001/copyparty/issues/new?labels=bug&template=bug_report.md');
+        exbox.innerHTML = basenames(html.join('\n')).replace(/<ghi>/, 'https://github.com/9001/copyparty/issues/new?labels=bug&template=bug_report.md');
         exbox.style.display = 'block';
     }
     catch (e) {