JSFiddle - React, Tailwind, and code Playground

HTML

<form method="post" action="switchDiv()">
    <select id="StateSelection" name="StateSelection">
        <option value="1">state 1</option>
        <option value="2">state 2</option>
        <option value="3">state 3</option>
        <option value="4">state 4</option>
        <option value="5">state 5</option>
    </select>
    <input type="button" class="bouton" name="test"/>
</form>    
    
    <div id="1" class="1">1</div>
    <div id="2" class="2">2</div>
    <div id="3" class="3">3</div>
    <div id="4" class="4">4</div>
    <div id="5" class="5">5</div>

JavaScript

$(function(){
    $(".2").hide();
    $(".3").hide();
    $(".4").hide();
    $(".5").hide();
});


switchDiv(value){
    $(".1").hide();
    $(".2").hide();
    $(".3").hide();
    $(".4").hide();
    $(".5").hide();
    $("." + value).toggle();
};