flooding-dom.js

(function() {
  let template = document.getElementById('testTemplate');

  function removeNode(node) {
    node.parentNode.removeChild(node);
  }

  for (let i = 0; i < 1000; ++i) {
    let clone = document.importNode(template.content, true);
    clone.querySelector('.test-class1').innerHTML = 'Firts Column_' + i;
    clone.querySelector('.test-class2').innerHTML = 'Second Column_' + i;
    clone.querySelector('.test-class3').innerHTML = 'Third Column_' + i;
    document.getElementById('parent').appendChild(clone);
  }
  
  let slice = Array.prototype.slice.call;

  slice(document.getElementsByClassName('test-class1'), 0).forEach(removeNode);
  slice(document.getElementsByClassName('test-class2'), 0).forEach(removeNode);
  slice(document.getElementsByClassName('test-class3'), 0).forEach(removeNode);
})();