JSFiddle - React, Tailwind, and code Playground

HTML

<div id="div">blabla</div>
    <div id="div1">blabla</div>

    <div style="margin-top: 50px;">
        <button id="btnGetSel">Valider</button>
    </div>

JavaScript

(function ($, w) {
    $.fn.BK = function (options) {
        var settings = $.extend(true, {}, { BkG: 'yellow' }, options);
        var n = $(this).attr("id");
        $("#" + n).css("background", settings.BkG);
    };

    $.fn.BK.GetInfo = function () {
        return true;
    };
}(jQuery));

$('#div').BK({BkG: 'red'});
$('#div1').BK({BkG: 'blue'});

$('#btnGetSel').click(function () {
   alert($('#div1').BK.GetInfo());
        return false;
    });