JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <select id="contentSelect">
        <option value="1">1</option>
        <option value="2">2</option>
        <option value="3">3</option>
    </select>
    
    <div id="content">Testtext</div>
    
    <div id="hiddenContents">
        <div id="hContent_1">Testtext</div>
        <div id="hContent_2">noch n' Testtext</div>
        <div id="hContent_3">Röttelpröm</div>
    </div>
</body>

CSS

#hiddenContents {
    display: none;
}

#content {
    width:500px;
    height: 500px;
    border: 2px solid black;
    margin: 50px;
    padding: 10px;
}

#contentSelect {
     width: 100px;   
}
}

JavaScript

$(function(){
    $("#contentSelect").change(function(){
        $("#content").html($("#hContent_"+$("#contentSelect option:selected").val()).html()); 
    });
});