JSFiddle - React, Tailwind, and code Playground
HTML
<span id="something\with\backslash" class="foo">
<div id="bar"></div>
</span>
<span id="something_without_backslash" class="foo">
<div id="bar2"></div>
</span>JavaScript
var $foo = $('.foo');
console.log( $foo );
console.log( $foo.find('#bar') );
console.log( $foo.find('#bar2') );