change button text in js/ajax after mp4 =>mp3 conversion in php

I am working on html table rows (which is two at this moment) as shown below in which on button click:

=> JS/jQuery code is called
=> and then convert.php script in which the conversion of mp4 into mp3 happens.

html/php code:

  <?php  foreach ($programs as $key => $program) {  ?> 
       <tr data-index="<?php echo $key; ?>">
          <td><input type="submit"  id="go-btn" name="go-button" value="Go" data-id="<?php echo $key; ?>" ></input></td>
       </tr>
    <?php }?>

convert.php:

 $f = $mp4_files[$_POST['id']];
 $parts = pathinfo($f); 
 switch ($parts['extension'])
 {  
     case 'mp4' :
         $filePath = $src_dir . DS . $f;
         system('C:\ffmpeg\bin\ffmpeg.exe -i ' . $filePath . ' -map 0:2 -ac 1 ' . $destination_dir . DS . $parts['filename'] . '.mp3', $result);    
         print_r("Hello World");
         break;                  
 } 

JS/jQuery code:

$("input[name='go-button']").click( function() {

  // Change the text of the button, and disable
  $(this).val("Converting").attr("disabled", "true");

});

As soon as the button is clicked from the html/php Code above, the text gets changed from Go to Converting in the UI because I have added JS/jQuery code in my codebase but this JS/jQuery code which I have added just change the text only.

It doesn't actually know that the Conversion is happening in the background.

Problem Statement:

I am wondering what modification I need to do in the JS/jQuery code above so that UI actually knows that conversion is happening in the background.

Probably, we need to add make establish some connection between JS/jQuery and php code above but I am not sure how we can do that.

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