3 files changed, 34 insertions, 2 deletions

diff --git a/runtime/js/11_workers.js b/runtime/js/11_workers.js
index 4989cd4b5..57f420728 100644
--- a/runtime/js/11_workers.js
+++ b/runtime/js/11_workers.js
@@ -3,6 +3,7 @@
 ((window) => {
   const core = window.Deno.core;
   const { Window } = window.__bootstrap.globalInterfaces;
+  const { getLocationHref } = window.__bootstrap.location;
   const { log, pathFromURL } = window.__bootstrap.util;
   const { defineEventHandler } = window.__bootstrap.webUtil;
   const build = window.__bootstrap.build.build;
@@ -127,6 +128,7 @@
 
     constructor(specifier, options = {}) {
       super();
+      specifier = String(specifier);
       const {
         deno = {},
         name = "unknown",
@@ -177,6 +179,16 @@
       const hasSourceCode = false;
       const sourceCode = decoder.decode(new Uint8Array());
 
+      if (
+        specifier.startsWith("./") || specifier.startsWith("../") ||
+        specifier.startsWith("/") || type == "classic"
+      ) {
+        const baseUrl = getLocationHref();
+        if (baseUrl != null) {
+          specifier = new URL(specifier, baseUrl).href;
+        }
+      }
+
       const { id } = createWorker(
         specifier,
         hasSourceCode,
diff --git a/runtime/js/99_main.js b/runtime/js/99_main.js
index f38d51936..284bef48c 100644
--- a/runtime/js/99_main.js
+++ b/runtime/js/99_main.js
@@ -9,6 +9,7 @@ delete Object.prototype.__proto__;
   const util = window.__bootstrap.util;
   const eventTarget = window.__bootstrap.eventTarget;
   const globalInterfaces = window.__bootstrap.globalInterfaces;
+  const location = window.__bootstrap.location;
   const dispatchMinimal = window.__bootstrap.dispatchMinimal;
   const build = window.__bootstrap.build;
   const version = window.__bootstrap.version;
@@ -196,6 +197,8 @@ delete Object.prototype.__proto__;
 
   // https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope
   const windowOrWorkerGlobalScope = {
+    Location: location.locationConstructorDescriptor,
+    location: location.locationDescriptor,
     Blob: util.nonEnumerable(fetch.Blob),
     ByteLengthQueuingStrategy: util.nonEnumerable(
       streams.ByteLengthQueuingStrategy,
@@ -290,7 +293,19 @@ delete Object.prototype.__proto__;
     defineEventHandler(window, "unload", null);
 
     runtimeStart(runtimeOptions);
-    const { args, noColor, pid, ppid, unstableFlag } = runtimeOptions;
+    const {
+      args,
+      location: locationHref,
+      noColor,
+      pid,
+      ppid,
+      unstableFlag,
+    } = runtimeOptions;
+
+    if (locationHref != null) {
+      location.setLocationHref(locationHref);
+      fetch.setBaseUrl(locationHref);
+    }
 
     registerErrors();
 
@@ -349,8 +364,11 @@ delete Object.prototype.__proto__;
       runtimeOptions,
       internalName ?? name,
     );
-    const { unstableFlag, pid, noColor, args } = runtimeOptions;
+    const { unstableFlag, pid, noColor, args, location: locationHref } =
+      runtimeOptions;
 
+    location.setLocationHref(locationHref);
+    fetch.setBaseUrl(locationHref);
     registerErrors();
 
     const finalDenoNs = {
diff --git a/runtime/js/README.md b/runtime/js/README.md
index b17fa22e5..7e3fe4345 100644
--- a/runtime/js/README.md
+++ b/runtime/js/README.md
@@ -38,6 +38,8 @@ Some Web APIs are using ops under the hood, eg. `console`, `performance`.
   [Body](https://developer.mozilla.org/en-US/docs/Web/API/Body) and
   [Headers](https://developer.mozilla.org/en-US/docs/Web/API/Headers): modern
   Promise-based HTTP Request API.
+- [location](https://developer.mozilla.org/en-US/docs/Web/API/Window/location)
+  and [Location](https://developer.mozilla.org/en-US/docs/Web/API/Location).
 - [FormData](https://developer.mozilla.org/en-US/docs/Web/API/FormData): access
   to a `multipart/form-data` serialization.
 - [Performance](https://developer.mozilla.org/en-US/docs/Web/API/Performance):