JSFiddle - React, Tailwind, and code Playground
HTML
<div class="container">
<input class=".start" id="Project_StartDate" name="Project.StartDate" value="6.9.2013 0:00:00" type="hidden"/>
<input class=".end" id="Project_EndDate" name="Project.EndDate" value="13.9.2013 0:00:00" type="hidden"/>
</div>
<p class="html">Html</p>
JavaScript
console.log($(".start").val());
console.log($(".container").find(".start").val());
console.log($(".container").children(".start").val());
console.log($(".html").html());