JSFiddle - React, Tailwind, and code Playground

HTML

<table style="width: 100%; background:transparent" border="0" cellspacing="0" cellpadding="0">

  <tbody><tr>
    <td>

        <!-- This div is making troubles -->   
        <div id="thing" >
          <p>Themensuche</p>
        </div>

    </td>
  </tr></tbody>
</table>
<button id="clickme">Change</button>

CSS

#thing{
    margin: 0; 
    border: 1px solid;
    border-color:blue;
    background-color:#CAE2F0; 
    align:right; 
    font-size: 150%; 
    font-weight: bold; 
    text-align:center;
    margin-right:5px;
    padding:  0;
}

JavaScript

$(function(event){
    $("#clickme").click(function(event){
        if($("#thing").css("border-color") == "rgb(0, 0, 255)"){
            $("#thing").css("border-color", "#CAE2F0");
        }else{
            $("#thing").css("border-color", "blue");
        }
    });
});