### Method

# WebKit2 WebView run_async_javascript_function_in_world

#### Declaration [src]

    void
    webkit_web_view_run_async_javascript_function_in_world (
      WebKitWebView* web_view,
      const gchar* body,
      GVariant* arguments,
      const char* world_name,
      GCancellable* cancellable,
      GAsyncReadyCallback callback,
      gpointer user_data
    )

#### Description [src]

Asynchronously run `body` in the script world with name `world_name` of the current page context in `web_view`. If WebKitSettings:enable-javascript is FALSE, this method will do nothing. This API differs from `webkit_web_view_run_javascript_in_world()` in that the JavaScript function can return a Promise and its result will be properly passed to the callback.

When the operation is finished, `callback` will be called. You can then call `webkit_web_view_run_javascript_in_world_finish()` to get the result of the operation.

For instance here is a dummy example that shows how to pass arguments to a JS function that returns a Promise that resolves with the passed argument:

    static void
    web_view_javascript_finished (GObject      *object,
                                  GAsyncResult *result,
                                  gpointer      user_data)
    {
        WebKitJavascriptResult *js_result;
        JSCValue               *value;
        GError                 *error = NULL;

        js_result = webkit_web_view_run_javascript_finish (WEBKIT_WEB_VIEW (object), result, &error);
        if (!js_result) {
            g_warning ("Error running javascript: %s", error->message);
            g_error_free (error);
            return;
        }

        value = webkit_javascript_result_get_js_value (js_result);
        if (jsc_value_is_number (value)) {
            gint32        int_value = jsc_value_to_string (value);
            JSCException *exception = jsc_context_get_exception (jsc_value_get_context (value));
            if (exception)
                g_warning ("Error running javascript: %s", jsc_exception_get_message (exception));
            else
                g_print ("Script result: %d\n", int_value);
            g_free (str_value);
        } else {
            g_warning ("Error running javascript: unexpected return value");
        }
        webkit_javascript_result_unref (js_result);
    }

    static void
    web_view_evaluate_promise (WebKitWebView *web_view)
    {
        GVariantDict dict;
        g_variant_dict_init (&dict, NULL);
        g_variant_dict_insert (&dict, "count", "u", 42);
        GVariant *args = g_variant_dict_end (&dict);
        const gchar *body = "return new Promise((resolve) => { resolve(count); });";
        webkit_web_view_run_async_javascript_function_in_world (web_view, body, arguments, NULL, NULL, web_view_javascript_finished, NULL);
    }

Available since: | 2.38
Deprecated since: | 2.40
Use `webkit_web_view_call_async_javascript_function()` instead.

#### Parameters

`body` | `const gchar*`
| The JavaScript function body.
| The data is owned by the caller of the function.
| The value is a NUL terminated UTF-8 string.
`arguments` | `GVariant`
| A `GVariant` with format `{&sv}` storing the function arguments. Function argument values must be one of the following types, or contain only the following GVariant types: number, string, array, and dictionary. `world_name` (nullable): the name of a `WebKitScriptWorld`, if no name (i.e. `NULL`) is provided, the default world is used. Any value that is not `NULL` is a distinct world.
| The data is owned by the caller of the function.
`world_name` | `const char*`
| No description available.
| The data is owned by the caller of the function.
| The value is a NUL terminated UTF-8 string.
`cancellable` | `GCancellable`
| A `GCancellable` or `NULL` to ignore.
| The argument can be `NULL`.
| The data is owned by the caller of the function.
`callback` | `GAsyncReadyCallback`
| A `GAsyncReadyCallback` to call when the script finished.
| The argument can be `NULL`.
`user_data` | `gpointer`
| The data to pass to callback function.
| The argument can be `NULL`.
| The data is owned by the caller of the function.