JSFiddle - React, Tailwind, and code Playground
by Ender
JavaScript
var page = '<html><head><title>This is my title!</title></head><body><div id="start"><p>A paragraph!</p><div>An internal div!</div></div><!-- start --><div>An external div!</div></body></html>';
var start = page.match(/(<div id="start">[\s\S]*?<\!-- start -->)/)[1];
alert(start);