JSFiddle - React, Tailwind, and code Playground

HTML

<select multiple id="multiple">
    <option value = 1>Uno</option>
    <option value = 2>Dos</option>
    <option value = 3>Tres</option>
    <option value = 4>Cuatro</option>
    <option value = 5>Cinco</option>
</select>

CSS

.blue{
    color:blue;
}

JavaScript

$("#multiple").on("click",function(){
    if($("#multiple option:selected").hasClass("blue")){
        $("#multiple option:selected").removeClass("blue");
    }else{
        $("#multiple option:selected").addClass("blue");
    }
});