diff --git a/client/dcwebui.js b/client/dcwebui.js
index b86246b..a39f57b 100644
--- a/client/dcwebui.js
+++ b/client/dcwebui.js
@@ -682,6 +682,7 @@ menu.reset = function() {
 	this.clear();
 	this.add(joinparts_getstr(),  toggle_joinparts);
 	this.add(desktop_notifications_fmtstr(), desktop_notifications_toggle);
+	this.add(warnonclose_fmtstr(), warnonclose_toggle);
 	this.add(timestamp_display(), timestamp_toggle);
 };
 
@@ -810,6 +811,8 @@ var timestamp_format_index = 0;
 
 var mainchat_unread_count = 0;
 
+var should_warn_on_close = false;
+
 var timestamp_display = function() {
 	return "Timestamp format: " + timestamp_names[timestamp_format_index];
 };
@@ -821,6 +824,17 @@ var timestamp_toggle = function(ev) {
 	$el.innerHTML = timestamp_display();
 };
 
+var warnonclose_fmtstr = function() {
+	return (should_warn_on_close ? "☑" : "☐") + " Confirm closing window";
+};
+
+var warnonclose_toggle = function(ev) {
+	var $el = ev.target || ev.srcElement;	
+	should_warn_on_close = !should_warn_on_close;
+	persistence_set("warnonclose", should_warn_on_close);
+	$el.innerHTML = warnonclose_fmtstr();
+};
+
 var desktop_notifications_enabled = false;
 
 var desktop_notifications_fmtstr = function() {
@@ -982,7 +996,7 @@ window.onload = function() {
 	};
 	
 	window.onbeforeunload = function (e) {
-		if (hub_state === STATE_ACTIVE) {
+		if (should_warn_on_close && hub_state === STATE_ACTIVE) {
 			// n.b. recent Firefox / Chrome don't display the custom message here.
 			var confirmationMessage = "Still connected to the hub \"" + hub_hubname + "\".\nAre you sure you want to close?";
 			e.returnValue = confirmationMessage;
@@ -993,6 +1007,8 @@ window.onload = function() {
 	
 	timestamp_format_index = persistence_get("timestamps", 0);
 	
+	should_warn_on_close = persistence_get("warnonclose");
+	
 	desktop_notifications_enabled = persistence_get("popups");
 	if (desktop_notifications_enabled) {
 		// prompt for permissions