var appendMe=1;
function appendFunction(){
var parentElement = document.getElementById('main-content');
var node = document.createElement("DIV");
var textnode = document.createTextNode("This was added dinamically");
node.appendChild(textnode);
node.id = 'new-div_' + appendMe;
var child = parentElement.children[2];
parentElement.insertBefore(node, child);
appendMe++;
}