JSFiddle - React, Tailwind, and code Playground

HTML

<input type='checkbox'/> 1<br/>
<input type='checkbox'/> 2<br/>
<input type='checkbox'/> 3<br/>
<input type='checkbox'/> 4<br/>

JavaScript

$('input[type=checkbox]').change(function(){
    if($('input[type=checkbox]:checked').length >= 2){
        $('input[type=checkbox]:not(:checked)').attr('disabled', true);
    } else{
        $('input[type=checkbox]:disabled').attr('disabled', false);
    }
});