DOMParser.js

fetch('https://json.org/example.html')
  .then( x => x.text())
  .then(function(html){ 
    var parser = new DOMParser(); 
    var doc = parser.parseFromString(html, "text/html"); 
    var pre = doc.querySelector('pre'); 
    var obj = JSON.parse(pre.innerHTML); 
    console.log(obj.glossary.GlossDiv.GlossList.GlossEntry.GlossDef.GlossSeeAlso[0]) 
  });