### Method

# WebKit UserContentManager register_script_message_handler

since: 2.40

#### Declaration [src]

    gboolean
    webkit_user_content_manager_register_script_message_handler (
      WebKitUserContentManager* manager,
      const char* name,
      const char* world_name
    )

#### Description [src]

Registers a new user script message handler in script world.

After it is registered, scripts can use `window.webkit.messageHandlers.<name>.postMessage(value)` to send messages. Those messages are received by connecting handlers to the `WebKitUserContentManager::script-message-received` signal. The handler name is used as the detail of the signal. To avoid race conditions between registering the handler name, and starting to receive the signals, it is recommended to connect to the signal before registering the handler name:

    WebKitWebView *view = webkit_web_view_new ();
    WebKitUserContentManager *manager = webkit_web_view_get_user_content_manager ();
    g_signal_connect (manager, "script-message-received::foobar",
                      G_CALLBACK (handle_script_message), NULL);
    webkit_user_content_manager_register_script_message_handler (manager, "foobar");

Registering a script message handler will fail if the requested name has been already registered before.

If `NULL` is passed as the `world_name`, the default world will be used.

The registered handler can be unregistered by using webkit_user_content_manager_unregister_script_message_handler().

Available since: 2.40

#### Parameters

`name`

  Type: `const char*`

  Name of the script message channel.

  The data is owned by the caller of the method.
  The value is a NUL terminated UTF-8 string.

`world_name`

  Type: `const char*`

  The name of a `WebKitScriptWorld`.

  The argument can be `NULL`.
  The data is owned by the caller of the method.
  The value is a NUL terminated UTF-8 string.

#### Return value

Type: `gboolean`

`TRUE` if message handler was registered successfully, or `FALSE` otherwise.