diff --git a/src/browser/webapi/navigation/NavigationEventTarget.zig b/src/browser/webapi/navigation/NavigationEventTarget.zig
index 581e06cc..44355ae1 100644
--- a/src/browser/webapi/navigation/NavigationEventTarget.zig
+++ b/src/browser/webapi/navigation/NavigationEventTarget.zig
@@ -17,9 +17,13 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
+const log = @import("../../../log.zig");
+
 const js = @import("../../js/js.zig");
 const Page = @import("../../Page.zig");
 
+const IS_DEBUG = @import("builtin").mode == .Debug;
+
 const EventTarget = @import("../EventTarget.zig");
 const NavigationCurrentEntryChangeEvent = @import("../event/NavigationCurrentEntryChangeEvent.zig");
 
@@ -43,10 +47,23 @@ pub fn dispatch(self: *NavigationEventTarget, event_type: DispatchType, page: *P
         };
     };
 
+    if (comptime IS_DEBUG) {
+        if (page.js.local == null) {
+            log.fatal(.bug, "null context scope", .{.src = "NavigationEventTarget.dispatch", .url = page.url});
+            std.debug.assert(page.js.local != null);
+        }
+    }
+
+    const func = @field(self, field) orelse return;
+
+    var ls: js.Local.Scope = undefined;
+    page.js.localScope(&ls);
+    defer ls.deinit();
+
     return page._event_manager.dispatchWithFunction(
         self.asEventTarget(),
         event,
-        page.js.toLocal(@field(self, field)),
+        ls.toLocal(func),
         .{ .context = "Navigation" },
     );
 }
diff --git a/src/browser/webapi/streams/ReadableStream.zig b/src/browser/webapi/streams/ReadableStream.zig
index dbb118b2..bdb88ae3 100644
--- a/src/browser/webapi/streams/ReadableStream.zig
+++ b/src/browser/webapi/streams/ReadableStream.zig
@@ -17,12 +17,16 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
-const js = @import("../../js/js.zig");
+const log = @import("../../../log.zig");
 
+const js = @import("../../js/js.zig");
 const Page = @import("../../Page.zig");
+
 const ReadableStreamDefaultReader = @import("ReadableStreamDefaultReader.zig");
 const ReadableStreamDefaultController = @import("ReadableStreamDefaultController.zig");
 
+const IS_DEBUG = @import("builtin").mode == .Debug;
+
 pub fn registerTypes() []const type {
     return &.{
         ReadableStream,
@@ -137,12 +141,25 @@ pub fn callPullIfNeeded(self: *ReadableStream) !void {
 
     self._pulling = true;
 
-    const pull_fn = self._page.js.toLocal(self._pull_fn) orelse return;
+    if (comptime IS_DEBUG) {
+        if (self._page.js.local == null) {
+            log.fatal(.bug, "null context scope", .{.src = "ReadableStream.callPullIfNeeded", .url = self._page.url});
+            std.debug.assert(self._page.js.local != null);
+        }
+    }
 
-    // Call the pull function
-    // Note: In a complete implementation, we'd handle the promise returned by pull
-    // and set _pulling = false when it resolves
-    try pull_fn.call(void, .{self._controller});
+    {
+        const func = self._pull_fn orelse return;
+
+        var ls: js.Local.Scope = undefined;
+        self._page.js.localScope(&ls);
+        defer ls.deinit();
+
+        // Call the pull function
+        // Note: In a complete implementation, we'd handle the promise returned by pull
+        // and set _pulling = false when it resolves
+        try ls.toLocal(func).call(void, .{self._controller});
+    }
 
     self._pulling = false;
 
diff --git a/src/browser/webapi/streams/ReadableStreamDefaultController.zig b/src/browser/webapi/streams/ReadableStreamDefaultController.zig
index f51d5798..7d868a11 100644
--- a/src/browser/webapi/streams/ReadableStreamDefaultController.zig
+++ b/src/browser/webapi/streams/ReadableStreamDefaultController.zig
@@ -17,12 +17,16 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
-const js = @import("../../js/js.zig");
+const log = @import("../../../log.zig");
 
+const js = @import("../../js/js.zig");
 const Page = @import("../../Page.zig");
+
 const ReadableStream = @import("ReadableStream.zig");
 const ReadableStreamDefaultReader = @import("ReadableStreamDefaultReader.zig");
 
+const IS_DEBUG = @import("builtin").mode == .Debug;
+
 const ReadableStreamDefaultController = @This();
 
 pub const Chunk = union(enum) {
@@ -79,7 +83,19 @@ pub fn enqueue(self: *ReadableStreamDefaultController, chunk: Chunk) !void {
         .done = false,
         .value = .fromChunk(chunk),
     };
-    self._page.js.toLocal(resolver).resolve("stream enqueue", result);
+
+    if (comptime IS_DEBUG) {
+        if (self._page.js.local == null) {
+            log.fatal(.bug, "null context scope", .{.src = "ReadableStreamDefaultController.enqueue", .url = self._page.url});
+            std.debug.assert(self._page.js.local != null);
+        }
+    }
+
+    var ls: js.Local.Scope = undefined;
+    self._page.js.localScope(&ls);
+    defer ls.deinit();
+
+    ls.toLocal(resolver).resolve("stream enqueue", result);
 }
 
 pub fn close(self: *ReadableStreamDefaultController) !void {
@@ -94,9 +110,21 @@ pub fn close(self: *ReadableStreamDefaultController) !void {
         .done = true,
         .value = .empty,
     };
-    for (self._pending_reads.items) |resolver| {
-        self._page.js.toLocal(resolver).resolve("stream close", result);
+
+    if (comptime IS_DEBUG) {
+        if (self._page.js.local == null) {
+            log.fatal(.bug, "null context scope", .{.src = "ReadableStreamDefaultController.close", .url = self._page.url});
+            std.debug.assert(self._page.js.local != null);
+        }
     }
+
+    for (self._pending_reads.items) |resolver| {
+        var ls: js.Local.Scope = undefined;
+        self._page.js.localScope(&ls);
+        defer ls.deinit();
+        ls.toLocal(resolver).resolve("stream close", result);
+    }
+
     self._pending_reads.clearRetainingCapacity();
 }