The parameter callback_addremove_mw specifies the name of the JavaScript method to be used as call back function when using the tool add/remove.
The parameter's structure: MyAddremoveResult(FEATURE, CENTERX, CENTERY, SUCCEEDED, KEYVALUES, SCALES, COORDSYS)
FEATURE: Value of the object, or NULL in case no object was found.
CENTERX: Center point x coordinate or NULL in case no object was found.
CENTERY: Center point y coordinate or NULL in case no object was found.
SUCCEEDED: it's TRUE if the search operation was successful or False if it failed.
KEYVALUES: List of values (keyvalue) from the selected features.
SCALES: Defines a list of the configured scales or NULL in case no scales are configured.
COORDSYS: Defines the coordinate system of the main map service. The coordinate system includes the epsg code (if available), the name of the coordinate system and its custom projection string (WKT). Consider that the custom projection string might have a length of about 700 characters.
Note: The methods name MyAddremoveResult is just an example as well as the parameter's names.
Example:
http://w-lap-rainer.synergis.intern:8080/WebOffice10R3_SP3_Latest/client_mapwidget/default.jsp?baseURL=http://w-lap-rainer.synergis.intern:8080/WebOffice10R3_SP3_Latest&project=SampleProject_Graz&width=600&height=400&combined_req=true&map_adv=true&activetools=ADDREMOVE&query=street_name&keyvalue=Murgasse&keyname=STR_NAME&returnkey=STR_NAME&callback_addremove_mw=parent.addremoveResult