insertBefore

add element as first child

HTML

<div class="main">
    <div class="content">Lorem</div>
    <div class="content">ipusm</div>
    <div class="content">dolores</div>
</div>

<div class="main">
   
</div>

JavaScript

var someParentObject = document.querySelector('.main');
var someChildObject = document.createElement("div");
someChildObject.setAttribute('class', 'content');
someChildObject.innerHTML = 'INTERLOPER';
//someParentObject.appendChild(someChildObject);
someParentObject.insertBefore(someChildObject,someParentObject.firstChild);