Visualforce Code-

<apex:page standardController="Feedbacks__c" docType="html-5.0">
    <apex:pageBlock >
        <apex:pageBlockSection >
            <apex:form >
                <style>
                    a {
  color: #337ab7;   
}   
p {
  margin-top: 1rem;
}
a:hover {
  color:#23527c;
}
a:visited {
  color: #8d75a3;
}

body {
    line-height: 1.5;
    font-family: sans-serif;
    word-wrap: break-word;
    overflow-wrap: break-word;
    color:black;
    margin:2em;
}

h1 {
    text-decoration: underline red;
    text-decoration-thickness: 3px;
    text-underline-offset: 6px;
    font-size: 220%;
    font-weight: bold;
}

h2 {
    font-weight: bold;
    color: #005A9C;
    font-size: 140%;
    text-transform: uppercase;
}

red {
    color: red;
}

#controls {
  display: flex;
  margin-top: 2rem;
  max-width: 28em;
} 

button {
  flex-grow: 1;
  height: 3.5rem;
  min-width: 2rem;
  border: none;
  border-radius: 0.15rem;
  background: #ed341d;
  margin-left: 2px;
  box-shadow: inset 0 -0.15rem 0 rgba(0, 0, 0, 0.2);
  cursor: pointer;
  display: flex;
  justify-content: center;
  align-items: center;
  color:#ffffff;
  font-weight: bold;
  font-size: 1.5rem;
}

button:hover, button:focus {
  outline: none;
  background: #c72d1c;
}

button::-moz-focus-inner {
  border: 0;
}

button:active {
  box-shadow: inset 0 1px 0 rgba(0, 0, 0, 0.2);
  line-height: 3rem;
}

button:disabled {
  pointer-events: none;
  background: lightgray;
}
button:first-child {
  margin-left: 0;
}

audio {
  display: block;
  width: 100%;
  margin-top: 0.2rem;
}

li {
  list-style: none;
  margin-bottom: 1rem;
}

#formats {
  margin-top: 0.5rem;
  font-size: 80%;
}

#recordingsList{
    max-width: 28em;
}
                </style>
                <script>
                  URL = window.URL || window.webkitURL;

var gumStream;            //stream from getUserMedia()
var rec;              //Recorder.js object
var input;              //MediaStreamAudioSourceNode we'll be recording

// shim for AudioContext when it's not avb. 
var AudioContext = window.AudioContext || window.webkitAudioContext;
var audioContext //audio context to help us record

var recordButton = document.getElementById("recordButton");
var stopButton = document.getElementById("stopButton");
var pauseButton = document.getElementById("pauseButton");
/*
//add events to those 2 buttons
recordButton.addEventListener("click", startRecording);
stopButton.addEventListener("click", stopRecording);
pauseButton.addEventListener("click", pauseRecording);
*/
function startRecording() {
  console.log("recordButton clicked");

  /*
    Simple constraints object, for more advanced audio features see
    https://addpipe.com/blog/audio-constraints-getusermedia/
  */
    var constraints = { audio: true, video:false }

  /*
      Disable the record button until we get a success or fail from getUserMedia() 
  */
  /*
  recordButton.disabled = true;
  stopButton.disabled = false;
  pauseButton.disabled = false
  */
  /*
      We're using the standard promise based getUserMedia() 
      https://developer.mozilla.org/en-US/docs/Web/API/MediaDevices/getUserMedia
  */

  navigator.mediaDevices.getUserMedia(constraints).then(function(stream) {
    console.log("getUserMedia() success, stream created, initializing Recorder.js ...");

    /*
      create an audio context after getUserMedia is called
      sampleRate might change after getUserMedia is called, like it does on macOS when recording through AirPods
      the sampleRate defaults to the one set in your OS for your playback device
    */
    audioContext = new AudioContext();

    //update the format 
    document.getElementById("formats").innerHTML="Format: 1 channel pcm @ "+audioContext.sampleRate/1000+"kHz"

    gumStream = stream;
    
    input = audioContext.createMediaStreamSource(stream);

    /* 
      Create the Recorder object and configure to record mono sound (1 channel)
      Recording 2 channels  will double the file size
    */
    rec = new Recorder(input,{numChannels:1})

    //start the recording process
    rec.record()

    console.log("Recording started");

  }).catch(function(err) {
      //enable the record button if getUserMedia() fails
      recordButton.disabled = false;
      stopButton.disabled = true;
      pauseButton.disabled = true
  });
}

function pauseRecording(){
  console.log("pauseButton clicked rec.recording=",rec.recording );
  if (rec.recording){
    //pause
    rec.stop();
    //pauseButton.innerHTML="Resume";
  }else{
    //resume
    rec.record()
    //pauseButton.innerHTML="Pause";

  }
}

function stopRecording() {
  console.log("stopButton clicked");

  //disable the stop button, enable the record too allow for new recordings
  /*Meenamma
  stopButton.disabled = true;
  recordButton.disabled = false;
  pauseButton.disabled = true;
  */
  //reset button just in case the recording is stopped while paused
 // pauseButton.innerHTML="Pause";
  
  //tell the recorder to stop the recording
  rec.stop();

  //stop microphone access
  gumStream.getAudioTracks()[0].stop();

  //create the wav blob and pass it on to createDownloadLink
  rec.exportWAV(createDownloadLink);
}

function createDownloadLink(blob) {
  
  var url = URL.createObjectURL(blob);
  var au = document.createElement('audio');
  var li = document.createElement('li');
  var link = document.createElement('a');

  //name of .wav file to use during upload and download (without extendion)
  var filename = new Date().toISOString();

  //add controls to the <audio> element
  au.controls = true;
  au.src = url;

  //save to disk link
  link.href = url;
  link.download = filename+".wav"; //download forces the browser to donwload the file using the  filename
  link.innerHTML = "Save to disk";

  //add the new audio element to li
  li.appendChild(au);
  
  //add the filename to the li
  li.appendChild(document.createTextNode(filename+".wav "))

  //add the save to disk link to li
  li.appendChild(link);
  
  //upload link
  var upload = document.createElement('a');
  upload.href="#";
  upload.innerHTML = "Upload";
  upload.addEventListener("click", function(event){
      var xhr=new XMLHttpRequest();
      xhr.onload=function(e) {
          if(this.readyState === 4) {
              console.log("Server returned: ",e.target.responseText);
          }
      };
      var fd=new FormData();
      fd.append("audio_data",blob, filename);
      xhr.open("POST","upload.php",true);
      xhr.send(fd);
  })
  li.appendChild(document.createTextNode (" "))//add a space in between
  li.appendChild(upload)//add the upload link to li

  //add the li element to the ol
  recordingsList.appendChild(li);
}
                </script>
                <html>
  <head>
    <title>Simple Recorder.js demo with record, stop and pause - addpipe.com</title>
    <!-- Latest compiled and minified Bootstrap CSS -->
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous"/>
    <link rel="stylesheet" type="text/css" href="style.css"/>
  </head>
  <body>
    <div id="controls">
     <input id="recordButton" type="button" value="Recorder" onclick="startRecording();"/>
     <input id="pauseButton" type="button" value="Pause" onclick="pauseRecording();"/>
     <input id="stopButton" type="button" value="Stop" onclick="stopRecording();"/>
    </div>
    <div id="formats">Format: start recording to see sample rate</div>
    <p><strong>Recordings:</strong></p>
    <ol id="recordingsList"></ol>
    <!-- inserting these scripts at the end to be able to use all the elements in the DOM -->
    <script src="https://cdn.rawgit.com/mattdiamond/Recorderjs/08e7abd9/dist/recorder.js"></script>
    <script src="js/app.js"></script>
  </body>
</html>