JSFiddle - React, Tailwind, and code Playground

HTML

<body onLoad="AlternarAbas('td_usua','div_usua')">
<table width="945" height="50"  align="left" valign="top" cellspacing="0" cellpadding="5" border="0" style="border-left: 1px solid #000000;" >
   <tr>
    <td height="20" width="50" class="menu" id="td_usua" onClick="AlternarAbas('td_usua','div_usua')">Usuario</td>
    <td height="20" width="50" class="menu" id="td_empr" onClick="AlternarAbas('td_empr','div_empr')">Empresa</td>
    <td height="20" width="50" class="menu" id="td_nota" onClick="AlternarAbas('td_nota','div_nota')">Nota Fiscal</td>
    <td height="20" width="50" class="menu" id="td_soft" onClick="AlternarAbas('td_soft','div_soft')">Software</td>
  </tr>
<tr>
	<td height="300" width="" class="tb-conteudo" colspan="4" align="left" valign="top" >  
		<div id="div_usua" class="conteudo" style="display: none; padding-top:5px;">
			<table align="left" border="0" width="2%">
				<tr>
					<td>
						<iframe style="border-radius:20px;" scrolling="no" src="#" width="900" height="400 " >
						</iframe>
					</td>
				</tr>
			</table>
		</div>

		<div id="div_empr" class="conteudo"  style="display: none; padding-top:5px;">
            <table border="0" width="" align="left"valign="top">
                <tr>
					<td>
                  	 <iframe style="border-radius:20px;" scrolling="no" src="#" width="900" height="400" >
					</iframe>
                   </td>
                </tr>
            </table>
        </div>
        
		<div id="div_nota" class="conteudo"  style="display: none; padding-top:5px;">
            <table border="0" width="" align="left"valign="top">
                <tr>
					<td>
                  	 <iframe style="border-radius:20px;" scrolling="no" src="#" width="900" height="400" >
					</iframe>
                   </td>
                </tr>
            </table>
        </div>
        
		<div id="div_soft" class="conteudo"  style="display: none; padding-top:5px;">
            <table border="0" width="" align="left"valign="top">
         ...

CSS

body, table {
font-family: Verdana, Arial, Helvetica, sans-serif;
font-size: 10px;
color: #000000;
}

.menu {
margin: 1px; 
font-family: Verdana, Arial, Helvetica, sans-serif;
font-size: 10px;
font-weight: bold;
color: #000033;
background-color: #FFFFFF;
border-right: 1px solid #000000;
border-top: 1px solid #000000;
border-bottom: 1px solid #000000;
padding: 5px;
cursor: hand;
text-align: center;
margin-top: 0px;
}

.menu-sel {
font-family: Verdana, Arial, Helvetica, sans-serif;
font-size: 10px;
font-weight: bold;
color: #0000FF;
background-color: #FFFAFA;
border-right: 1px solid #000000;
border-top: 2px solid #000000;
padding: 5px;
cursor: hand;
margin: 0px; 
margin-top: 0px;
}

.tb-conteudo {
border-right: 1px solid #000000;
border-bottom: 1px solid #000000;
margin: 0px; 
}

.conteudo {
font-family: Verdana, Arial, Helvetica, sans-serif;
font-size: 10px;
font-weight: normal;
color: #000033;
background-color: ;
padding: 5px;
margin:0px;
width:500px;
}

JavaScript

function stAba(menu,conteudo)
{
  this.menu = menu;
  this.conteudo = conteudo;
}

var arAbas = new Array();
arAbas[0] = new stAba('td_usua','div_usua');
arAbas[1] = new stAba('td_empr','div_empr');
arAbas[2] = new stAba('td_nota','div_nota');
arAbas[3] = new stAba('td_soft','div_soft');



function AlternarAbas(menu,conteudo)
{
  for (i=0;i<arAbas.length;i++)
  {
   m = document.getElementById(arAbas[i].menu);
   m.className = 'menu';
   c = document.getElementById(arAbas[i].conteudo)
   c.style.display = 'none';
  }
  m = document.getElementById(menu)
  m.className = 'menu-sel';
  c = document.getElementById(conteudo)
  c.style.display = '';
}