JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<table>
  <thead>
    <tr>
        <th>srno</th>
        <th>name</th>
        <th>email</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>1</td>
      <td>Jhon One</td>
      <td>Doe one</td>
    </tr>
    <tr>
      <td>2</td>
      <td>Jhon two</td>
      <td>Doe Two</td>
    </tr>
  </tbody>
</table>

<button>
convert
</button>

JavaScript

$("button").click(function(){
	var json = html2json();
  alert(json);
});

function html2json() {
   var json = '{';
   var otArr = [];
  // var i = 1;
   var tbl2 = $('table tbody tr').each(function(e) {        
      x = $(this).children();
      var itArr = [];
      x.each(function() {
         itArr.push('"' + $(this).text() + '"');
      });
      otArr.push('"' + (Number(e) + 1) + '": {' + itArr.join(',') + '}');
   })
   json += otArr.join(",") + '}'

   return json;
}