diff --git a/pyscriptjs/directoryManifest.mjs b/pyscriptjs/directoryManifest.mjs
index 4fb5756c..ef8a1000 100644
--- a/pyscriptjs/directoryManifest.mjs
+++ b/pyscriptjs/directoryManifest.mjs
@@ -2,7 +2,7 @@
 // 1. esbuild.mjs
 // 2. Jest setup.ts
 
-import { join } from 'path';
+import path, { join } from 'path';
 import { opendir, readFile } from 'fs/promises';
 
 /**
@@ -38,7 +38,16 @@ async function _directoryManifestHelper(root, dir, result) {
             result.dirs.push(entry);
             await _directoryManifestHelper(root, entry, result);
         } else if (d.isFile()) {
-            result.files.push([entry, await readFile(join(root, entry), { encoding: 'utf-8' })]);
+            result.files.push([normalizePath(entry), await readFile(join(root, entry), { encoding: 'utf-8' })]);
         }
     }
 }
+
+/**
+ * Normalize paths under different operating systems to
+ * the correct path that will be used for src on browser.
+ * @param {string} originalPath
+ */
+function normalizePath(originalPath) {
+    return path.normalize(originalPath).replace(/\\/g, '/');
+}
diff --git a/pyscriptjs/esbuild.mjs b/pyscriptjs/esbuild.mjs
index f455f314..5d844265 100644
--- a/pyscriptjs/esbuild.mjs
+++ b/pyscriptjs/esbuild.mjs
@@ -1,11 +1,12 @@
 import { build } from 'esbuild';
 import { spawn } from 'child_process';
-import { dirname, join } from 'path';
+import { join } from 'path';
 import { watchFile } from 'fs';
 import { cp, lstat, readdir } from 'fs/promises';
 import { directoryManifest } from './directoryManifest.mjs';
+import { fileURLToPath } from 'url';
 
-const __dirname = dirname(new URL(import.meta.url).pathname);
+const __dirname = fileURLToPath(new URL('.', import.meta.url));
 
 const production = !process.env.NODE_WATCH || process.env.NODE_ENV === 'production';