nsITextInputProcessorCallback is defined for receiving requests and notifications to IME from Gecko. This interface has a "function" attribute. Therefore, JS-IME can implement this as a function.

Example of simple JS-IME:

var simpleIME = {
  _hasFocus: false,
  _hasRightsToCompose: false,
  _TIP: null,
  _callback: function simpleIME_callback(aTIP, aNotification)
  {
    try {
      switch (aNotification.type) {
        case "request-to-commit":
          aTIP.commitComposition();
          break;
        case "request-to-cancel":
          aTIP.cancelComposition();
          break;
        case "notify-focus":
          this._hasFocus = true;
          break;
        case "notify-blur":
          this._hasFocus = false;
          break;
        case "notify-detached":
          this._hasFocus = false;
          this._hasRightsToCompose = false;
          break;
      }
      return true;
    } catch (e) {
      return false;
    }
  },
  setComposition: function simpleIME_setComposition(aText, aClauses, aCaret)
  {
    if (!this._TIP) {
      this._TIP = Components.classes["@mozilla.org/text-input-processor;1"].
                    createInstance(Components.interfaces.nsITextInputProcessor);
    }
    if (!this._TIP.beginInputTransaction(window, this._callback)) {
      return false;
    }
    ...
  },
}

Method overview

Methods

onNotify()

This is called when Gecko requests or notifies something to IME.

boolean onNotify(in nsITextInputProcessor aTextInputProcessor,
                 in nsITextInputProcessorNotification aNotification);

Parameters

aTextInputProcessor

The instance which receives the notification. If the handler needs to do something with composition, you can use this.

aNotification

A notification or request. See the document of nsITextInputProcessorNotification for the details.

Return value

If this handles the notification normally or does nothing, it should return true. Otherwise, false.