var campaigns = document.getElementsByClassName("campaign");

for (var i=0, max= campaigns.length; i <= max; i++) {

//This alert works - alert("Campaign" + i);

var newDiv = document.createElement('div');

   newDiv.id = 'example'+i;
   newDiv.className = 'examples';
   newDiv.style.color = "red";
   document.appendChild(newDiv);

};