Add/remove HTML inside div using JavaScript

You can do something like this.

function addRow() {
  const div = document.createElement('div');

  div.className = 'row';

  div.innerHTML = `
    <input type="text" name="name" value="" />
    <input type="text" name="value" value="" />
    <label> 
      <input type="checkbox" name="check" value="1" /> Checked? 
    </label>
    <input type="button" value="-" onclick="removeRow(this)" />
  `;

  document.getElementById('content').appendChild(div);
}

function removeRow(input) {
  document.getElementById('content').removeChild(input.parentNode);
}

You can use this function to add an child to a DOM element.

function addElement(parentId, elementTag, elementId, html) 

 {


// Adds an element to the document


    var p = document.getElementById(parentId);
    var newElement = document.createElement(elementTag);
    newElement.setAttribute('id', elementId);
    newElement.innerHTML = html;
    p.appendChild(newElement);
}



function removeElement(elementId) 

{

    // Removes an element from the document
    var element = document.getElementById(elementId);
    element.parentNode.removeChild(element);
}

Another solution is to use getDocumentById and insertAdjacentHTML.

Code:

function addRow() {

 const  div = document.getElementById('content');

 div.insertAdjacentHTML('afterbegin', 'PUT_HTML_HERE');

}

Check here, for more details: Element.insertAdjacentHTML()

To my most biggest surprise I present to you a DOM method I've never used before googeling this question and finding ancient insertAdjacentHTML on MDN (see CanIUse?insertAdjacentHTML for a pretty green compatibility table).

So using it you would write

function addRow () {
  document.querySelector('#content').insertAdjacentHTML(
    'afterbegin',
    `<div class="row">
      <input type="text" name="name" value="" />
      <input type="text" name="value" value="" />
      <label><input type="checkbox" name="check" value="1" />Checked?</label>
      <input type="button" value="-" onclick="removeRow(this)">
    </div>`      
  )
}

function removeRow (input) {
  input.parentNode.remove()
}

<input type="button" value="+" onclick="addRow()">

<div id="content">
</div>