void addEventListener(
    in DOMString type, 
    in EventListener listener, 
    in boolean useCapture); 

void close(); 

boolean dispatchEvent(
    in Event evt) raises(EventException); 

void removeEventListener(
    in DOMString type, 
    in EventListener listener, 
    in boolean useCapture); 

const unsigned short CLOSED = 2; 

const unsigned short CONNECTING = 0; 

attribute EventListener onerror; 

attribute EventListener onmessage; 

attribute EventListener onopen; 

const unsigned short OPEN = 1; 

readonly attribute unsigned short readyState; 

readonly attribute DOMString URL;