## Steps { #steps }

So, let's say you have a frontend running in your browser at `http://localhost:8080`, and its JavaScript is trying to communicate with a backend running at `http://localhost` (because we don't specify a port, the browser will assume the default port `80`).

///

/// info

To declare cookies, you need to use `Cookie`, because otherwise the parameters would be interpreted as query parameters.

///

/// info

Have in mind that, as **browsers handle cookies** in special ways and behind the scenes, they **don't** easily allow **JavaScript** to touch them.

    /**
     * Enumeration of supported browser types for user agent detection.
     * Each type represents a major browser family that can be detected
     * from the User-Agent header string.
     */
    public enum UserAgentType {
        /** Internet Explorer and Trident-based browsers */
        IE,
        /** Mozilla Firefox browser */
        FIREFOX,
        /** Google Chrome browser */
        CHROME,

* SSE - [Server-sent events](https://html.spec.whatwg.org/multipage/server-sent-events.html#server-sent-events)

Where the spec is ambiguous, OkHttp follows modern user agents such as popular Browsers or common HTTP Libraries.

OkHttp is principled and avoids being overly configurable, especially when such configuration is
to workaround a buggy server, test invalid scenarios or that contradict the relevant RFC.

```
http://localhost:8000/v1/agents/multivac
```

Even though the host of the malicious website and the local app is different, the browser won't trigger a CORS preflight request because:

* It's running without any authentication, it doesn't have to send any credentials.
* The browser thinks it's not sending JSON (because of the missing `Content-Type` header).

    // 3) Caller specified but assuming the visible defaults in MODERN_CIPHER_SUITES are rejigged
    // to match legacy i.e. the platform/provider
    //
    // Opting for 2 here and keeping MODERN_TLS in line with secure browsers.
    cipherSuitesAsString.intersect(socketEnabledCipherSuites, CipherSuite.ORDER_BY_NAME)
  } else {
    socketEnabledCipherSuites
  }

internal fun MediaType?.chooseCharset(): Pair<Charset, MediaType?> {

You can see the defined cookies in the docs UI at `/docs`:

<div class="screenshot">
<img src="/img/tutorial/cookie-param-models/image01.png">
</div>

/// info

Have in mind that, as **browsers handle cookies** in special ways and behind the scenes, they **don't** easily allow **JavaScript** to touch them.

You can stream data to the client using **Server-Sent Events** (SSE).

This is similar to [Stream JSON Lines](stream-json-lines.md), but uses the `text/event-stream` format, which is supported natively by browsers with the [`EventSource` API](https://developer.mozilla.org/en-US/docs/Web/API/EventSource).

/// info

Added in FastAPI 0.135.0.

///

## What are Server-Sent Events? { #what-are-server-sent-events }

            if (e.key === 'Enter' && !e.shiftKey && !e.isComposing) {
                e.preventDefault();
                sendMessage();
            }
        });

        // Handle IME composition for older browsers
        elements.chatInput.on('compositionstart', function() {
            elements.chatInput.data('composing', true);
        });
        elements.chatInput.on('compositionend', function() {

  /** Returns true if this cookie should be limited to only HTTPS requests. */
  @get:JvmName("secure") val secure: Boolean,
  /**
   * Returns true if this cookie should be limited to only HTTP APIs. In web browsers this prevents
   * the cookie from being accessible to scripts.
   */
  @get:JvmName("httpOnly") val httpOnly: Boolean,
  /**
   * Returns true if this cookie does not expire at the end of the current session.
   *