JSFiddle - React, Tailwind, and code Playground

HTML

<form method="POST">            
            
<table id="dataTable" width="100%"  border="0">
    <tr>
        <td><input value="" type="checkbox" name="seiten[0][aktiv]"/ checked="checked"></td>
        <td><input type="text" style="width: 500px" name="seiten[0][value]"/></td>
        <td>
          <img src="http://findicons.com/files/icons/1156/fugue/16/plus_button.png" onclick="addRow('dataTable')">
          <img src="http://findicons.com/files/icons/1156/fugue/16/minus_button.png" onclick="deleteRow('dataTable')">
        </td>
        <td>

        </td>
    </tr>
</table>

<input type="submit" name="Submit" value="Daten jetzt Speichern" />
</form>

JavaScript

function addRow(tableID) {

		var table = document.getElementById(tableID);

		var rowCount = table.rows.length;
		var row = table.insertRow(rowCount);

		var colCount = table.rows[0].cells.length;

		for(var i=0; i<colCount; i++) {

			var newcell = row.insertCell(i);

			newcell.innerHTML = table.rows[0].cells[i].innerHTML;
			//alert(newcell.childNodes);
			switch(newcell.childNodes[0].type) {
				case "text":
						newcell.childNodes[0].value = "";
						break;
				case "checkbox":
						newcell.childNodes[0].checked = true;
						break;
				case "select-one":
						newcell.childNodes[0].selectedIndex = 0;
						break;
			}
		}
	}

	function deleteRow(tableID) {
		try {
		var table = document.getElementById(tableID);
		var rowCount = table.rows.length;

		for(var i=0; i<rowCount; i++) {
			var row = table.rows[i];
			var chkbox = row.cells[2].childNodes[0];
			if(null != chkbox && true == chkbox.checked) {
				if(rowCount <= 1) {
					alert("Cannot delete all the rows.");
					break;
				}
				table.deleteRow(i);
				rowCount--;
				i--;
			}


		}
		}catch(e) {
			alert(e);
		}
	}