JSFiddle - React, Tailwind, and code Playground

HTML

<div id="disp"></div>

JavaScript

var sTxt = "<body><div></div><div></div><a></a><bla></bla></body>";
var startWith = "<body>",
    endWith = "</body>";
var iStart = sTxt.search(startWith);
var iEnd = sTxt.search(endWith);

console.log(sTxt);
console.log(iStart);
console.log(iEnd);
sTxt = sTxt.substring(iStart+startWith.length, iEnd)
console.log(sTxt);

$("#disp").text(sTxt);