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 otArr = [];
  var tblHeaders = Array.from($('table thead tr')
   	.children())
    .map(header => $(header).text());  
  var tbl2 = $('table tbody tr').each(function(e) {        
    const values = Array.from($(this).children());
    const row = {};
    for (let i = 0; i < tblHeaders.length; i++){    	
    	row[tblHeaders[i]] = $(values[i]).text();
    }
    otArr.push({
    	[e+1]: row
    })      
  })
  json = JSON.stringify(otArr);  
  return json;
}