diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 32398fe20..9c44792f9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -30,3 +30,7 @@ jobs:
 
       - name: Run tests
         run: npm test
+
+      - name: Run tests with fetch()
+        run: npm run test:node-fetch
+        if: ${{ matrix.node-version == '20' }}
diff --git a/lib/transports/polling-fetch.ts b/lib/transports/polling-fetch.ts
index 882b3192d..b9d1c2f0e 100644
--- a/lib/transports/polling-fetch.ts
+++ b/lib/transports/polling-fetch.ts
@@ -17,36 +17,35 @@ export class Fetch extends Polling {
     }
   }
 
-  override async doPoll() {
-    try {
-      const res = await this._fetch();
+  override doPoll() {
+    this._fetch()
+      .then((res) => {
+        if (!res.ok) {
+          return this.onError("fetch read error", res.status, res);
+        }
 
-      if (!res.ok) {
-        return this.onError("fetch read error", res.status, res);
-      }
-
-      const data = await res.text();
-      this.onData(data);
-    } catch (e) {
-      this.onError("fetch read error", e);
-    }
+        res.text().then((data) => this.onData(data));
+      })
+      .catch((err) => {
+        this.onError("fetch read error", err);
+      });
   }
 
-  override async doWrite(data: string, callback: () => void) {
-    try {
-      const res = await this._fetch(data);
+  override doWrite(data: string, callback: () => void) {
+    this._fetch(data)
+      .then((res) => {
+        if (!res.ok) {
+          return this.onError("fetch write error", res.status, res);
+        }
 
-      if (!res.ok) {
-        return this.onError("fetch write error", res.status, res);
-      }
-
-      callback();
-    } catch (e) {
-      this.onError("fetch write error", e);
-    }
+        callback();
+      })
+      .catch((err) => {
+        this.onError("fetch write error", err);
+      });
   }
 
-  private async _fetch(data?: string) {
+  private _fetch(data?: string) {
     const isPost = data !== undefined;
     const headers = new Headers(this.opts.extraHeaders);
 
@@ -56,18 +55,18 @@ export class Fetch extends Polling {
 
     this.cookieJar?.appendCookies(headers);
 
-    const res = await fetch(this.uri(), {
+    return fetch(this.uri(), {
       method: isPost ? "POST" : "GET",
       body: isPost ? data : null,
       headers,
       credentials: this.opts.withCredentials ? "include" : "omit",
-    });
-
-    if (this.cookieJar) {
-      // @ts-ignore getSetCookie() was added in Node.js v19.7.0
-      this.cookieJar.parseCookies(res.headers.getSetCookie());
-    }
+    }).then((res) => {
+      if (this.cookieJar) {
+        // @ts-ignore getSetCookie() was added in Node.js v19.7.0
+        this.cookieJar.parseCookies(res.headers.getSetCookie());
+      }
 
-    return res;
+      return res;
+    });
   }
 }
diff --git a/lib/transports/xmlhttprequest.ts b/lib/transports/xmlhttprequest.ts
index 145d183a2..6d52c45a3 100644
--- a/lib/transports/xmlhttprequest.ts
+++ b/lib/transports/xmlhttprequest.ts
@@ -95,7 +95,7 @@ export class CookieJar {
 
     if (cookies.length) {
       xhr.setDisableHeaderCheck(true);
-      xhr.set("cookie", cookies.join("; "));
+      xhr.setRequestHeader("cookie", cookies.join("; "));
     }
   }
 
diff --git a/package.json b/package.json
index 6d76fa1cf..fd02316f3 100644
--- a/package.json
+++ b/package.json
@@ -93,7 +93,7 @@
   },
   "scripts": {
     "compile": "rimraf ./build && tsc && tsc -p tsconfig.esm.json && ./postcompile.sh",
-    "test": "npm run format:check && npm run compile && if test \"$BROWSERS\" = \"1\" ; then npm run test:browser; else npm run test:node && npm run test:node-fetch; fi",
+    "test": "npm run format:check && npm run compile && if test \"$BROWSERS\" = \"1\" ; then npm run test:browser; else npm run test:node; fi",
     "test:node": "mocha --bail --require test/support/hooks.js test/index.js test/webtransport.mjs",
     "test:node-fetch": "USE_FETCH=1 npm run test:node",
     "test:browser": "zuul test/index.js",
diff --git a/test/connection.js b/test/connection.js
index 49dd1257c..231393127 100644
--- a/test/connection.js
+++ b/test/connection.js
@@ -199,7 +199,9 @@ describe("connection", function () {
 
   if (env.browser && typeof addEventListener === "function") {
     it("should close the socket when receiving a beforeunload event", (done) => {
-      const socket = new Socket();
+      const socket = new Socket({
+        closeOnBeforeunload: true,
+      });
 
       const createEvent = (name) => {
         if (typeof Event === "function") {