JSFiddle - React, Tailwind, and code Playground
HTML
<input id="check1" type="checkbox" checked/>
<p></p>
JavaScript
$("#check1").change(function(){
var value = $("#check1").is(":checked");
alert(value);
});
<input id="check1" type="checkbox" checked/>
<p></p>
$("#check1").change(function(){
var value = $("#check1").is(":checked");
alert(value);
});