WebSpeechAPI to run on browser

i’m working as a software developer trainee in an organisation and
i’m trying to achieve a webspeechApi code which can access browser..
suppose if i say ‘open facebook’ the browser should open facebook.
i’ve tried using annyang but i dont wanna add any external libraries because of
security reasons

                                <script>
                                    var message = document.querySelector('#message');

                                    var SpeechRecognition = SpeechRecognition || webkitSpeechRecognition;
                                    var SpeechGrammarList = SpeechGrammarList || webkitSpeechGrammarList;

                                    var grammar = '#JSGF V1.0;'

                                    var recognition = new SpeechRecognition();
                                    var speechRecognitionList = new SpeechGrammarList();
                                    speechRecognitionList.addFromString(grammar, 1);
                                    recognition.grammars = speechRecognitionList;
                                    recognition.lang = 'en-US';
                                    recognition.interimResults = false;

                                    recognition.onresult = function(event) {
                                        var last = event.results.length - 1;
                                    
                                    
                                        
                                    var commands = {

                                            'open facebook' : open,
                                            
                                            }
                                            
                                            function openfacebook(){
                                            alert('opening facebook')
                                            console.log('open facebook');
                                            location.href = 'https://www.facebook.com/';
                                            
                                            }
                                    
                                    };

                                    recognition.onspeechend = function() {
                                        recognition.stop();
                                    };

                                    recognition.onerror = function(event) {
                                        message.textContent = 'Error occurred in recognition: ' + event.error;
                                    }        

                                    document.querySelector('#btnGiveCommand').addEventListener('click', function(){
                                        recognition.start();

                                    });


                                </script>