What is the difference of an already 'created' element stored in a variable or creating it from scratch
var box = document.getElementById("set");
var bc1 = document.getElementById("bc1");
bc1.onclick = function() {
var div1 = "<div class='caja1'>Hola</div>";
box.innerHTML = div1;
}
// ELEMENTO CREADO DESDE CERO
var bc2 = document.getElementById("bc2");
bc2.onclick = function() {
var crear = document.createElement("div");
crear.innerHTML = "Hola 2";
crear.setAttribute("class", "caja2");
box.appendChild(crear);
}
<div id="set"></div>
<button id="bc1">Crear 1</button>
<button id="bc2">Crear 2</button>