JSFiddle - React, Tailwind, and code Playground

by Seguret

HTML

GENNAIO 2018
<table>
	<thead>
		<tr>
			<td class="inteBloc">LUNEDI</td>
			<td class="inteBloc">MARTEDI</td>
			<td class="inteBloc">MERCOLEDI</td>
			<td class="inteBloc">GIOVEDI</td>
			<td class="inteBloc">VENERDI</td>
			<td class="inteBloc">SABATO</td>
			<td class="inteBloc">DOMENICA</td>
			<td class="inteBloc">Ore</td>
			<td class="inteBloc">FestivitĂ </td>
		</tr>
	</thead>
	<tbody>
    <thead class="row_int">
        <tr>
          <td class="numDay"></td>
          <td class="numDay"></td>
          <td class="numDay"></td>
          <td class="numDay"></td>
          <td class="numDay"></td>
          <td class="numDay"></td>
          <td class="numDay"></td>
          <td class="no"></td>
          <td class="no"></td>
        </tr>
        <tr>
          <td></td>
          <td></td>
          <td></td>
          <td></td>
          <td></td>
          <td></td>
          <td></td>
          <td class="no"></td>
          <td class="no"></td>
        </tr>
    </thead>
	</tbody>
</table>

JavaScript

let day;let CLASS;
//var TD = document.getElementsByTagName('td');
let row_int = document.getElementByClassName('row_int');
let numDay = document.getElementsByClassName('numDay');

numDay = row_int + numDay;

var data = new Date(2018, 0, 1);
var millisec =  data.getTime();

for(let i = 0 ; i < numDay.length ; i++){
		if(numDay[i].className=='inteBloc' || numDay[i].className=='no') continue
   
    
    data.setTime(millisec);
   
    numDay[i].textContent=data.getDate();
    
    millisec += 86400000;
}