JSFiddle - React, Tailwind, and code Playground
HTML
<div id='test#1'>test1</div>
<div id='test#2'>test2</div>
CSS
#test\#1{color: red;}
JavaScript
$('#test\\#2').css('color','blue');
<div id='test#1'>test1</div>
<div id='test#2'>test2</div>
#test\#1{color: red;}
$('#test\\#2').css('color','blue');