JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <ul id="seasonsDropDown">
      <li data-season="FALL 2013 HAUTE COUTURE">FALL 2013 HAUTE COUTURE
        <ul class="designers">
          <li data-designer="Alexander Wang">Alexander Wang</li>
          <li data-designer="BCBG MAX Azria">BCBG MAX Azria</li>
          <li data-designer="Diane con Fursternberg">Diane con Fursternberg</li>
          <li data-designer="Diane Von De">Diane Von De</li>
        </ul>
     </li>
    </ul>
</body>

JavaScript

$(document).ready(function(){
        var designersArrAll = [];
        var designersArrSelected = ["Von Blan","Foo Can","Diane con Fursternberg","BCBG MAX Azria"];
         var i = 0;
         
         
         $(".designers>li").each(function(){
             designersArrAll[i++] = $(this).attr("data-designer");
         });
         
        $(".designers>li").each(function(){
            designer = $(this).attr("data-designer");
            designersArrAll[i++] = designer;           
            if ( contains( designersArrSelected , designer) ) {
                // do something here
                $(this).css('background', 'yellow');
            }
        });
        function contains(a, obj) {
            for (var i = 0; i < a.length; i++) {
                    if (a[i] === obj) {
                        return true;
                    }
                }
                return false;
        }
    });