JSFiddle - React, Tailwind, and code Playground

HTML

<html><body><div id="test">test</div></body></html>

JavaScript

$(function () {

    console.log("\n\n");
    
    console.log($('#test').html());

    // the result for these is "undefined."
    console.log($('<html><body><div id="test">test</div></body></html>').find('body').html());
    console.log($('<html><body><div id="test">test</div></body></html>').find('#test').html());
    console.log($('<div id="test">test</div>').find('#test').html());

    // the result to these is correct.  the only addition was adding a plain wrapper div.
    console.log($('<html><body><div><div id="test">test</div></div></body></html>').find('#test').html());
    console.log($('<div><div id="test">test</div></div>').find('#test').html());

});