- type && arg1 && X_ViewPort_document[ 'listenOnce' ]( type, arg1, arg2, arg3 );
- return X.Doc;
+
+ f = X_Closure_classifyCallbackArgs( arg1, arg2, arg3 );
+ if( !f.cbKind ){
+ X_ViewPort_document[ 'listenOnce' ]( type, this, arg1 );
+ } else
+ if( f.cbKind === X_CLOSURE_FUNC_ONLY ){
+ X_ViewPort_document[ 'listenOnce' ]( type, this, f.func, f.supplement );
+ };
+ X_ViewPort_document[ 'listenOnce' ]( type, arg1, arg2, arg3 );
+ return X[ 'Doc' ];