JSFiddle - React, Tailwind, and code Playground

HTML

<script type="text/javascript" src="http://code.jquery.com/jquery-latest.js"></script> 
<script type="text/javascript" src="http://jzaefferer.github.com/jquery-validation/jquery.validate.js"></script>

<input id='sendList' type='checkbox' name='selectList[]' value='$set[ListID]'>

JavaScript

$("#selectList").validate({
    rules: {
        'selectList[]': {
            required: true,
            minlength: 1
        }
    }
});