JSFiddle - React, Tailwind, and code Playground

HTML

<form>
  <fieldset>
    <legend><h3>Rediger eller slet blogindlæg</h3></legend>
    <table cellpadding="2" id="rediger_blog_1">
        <tr>
            <td class="headline">Dette er en overskrift!</td>
            <td class="option"><input class="option" type="submit" value="Rediger" onclick="show_edit('rediger_blog');"/></td>
            <td class="option"><input class="option" type="submit" value="Slet"/></td>
        </tr>
        </table>
    <table cellpadding="2" id="rediger_blog_2" style="display:none;">
        <tr>
            <td>Overskrift:</td>
            <td><input type="text" /></td>
        </tr>
        <tr>
            <td>Indhold:</td>
            <td><input type="text" /></td>
        </tr>
        <tr>
            <td><input type="submit" value="Gem indlæg" class="save" onclick="hide_edit('rediger_blog');"/></td>
            <td>&nbsp;</td>
        </tr>        
    </table>
  </fieldset>
</form>

JavaScript

function show_edit(ID) {
            $("#"+ID+"_1").hide();    
            $("#"+ID+"_2").show();        
}
    function hide_edit(ID) {
            $("#"+ID+"_2").hide();            
            $("#"+ID+"_1").show();    
}