JSFiddle - React, Tailwind, and code Playground
HTML
<input type="button" id="change_background" value="Change background" />
JavaScript
$( "#change_background" ).on( "click", function() {
$("body").first().css("background-color","red");
});
<input type="button" id="change_background" value="Change background" />
$( "#change_background" ).on( "click", function() {
$("body").first().css("background-color","red");
});