public static int readVersion( Handshakedata handshakedata ) {
		String vers = handshakedata.getFieldValue( "Sec-WebSocket-Version" );
		if( vers.length() > 0 ) {
			int v;
			try {
				v = new Integer( vers.trim() );
				return v;
			} catch ( NumberFormatException e ) {
				return -1;
			}
		}
		return -1;
	}