var previousDiv = null;
var previousClasses = null;

function callItOut(divName) {
  if (document.getElementById) {
    currentClasses = document.getElementById(divName).className;
    document.getElementById(divName).className += " articleHighlight";
    if (previousDiv != null) {
      document.getElementById(previousDiv).className = previousClasses;
    }
    previousDiv = divName;
    previousClasses = currentClasses;
  }
}

function unCallIt(divName) {
  if (document.getElementById) {
    document.getElementById(divName).className = previousClasses;
    previousDiv = null;
    previousClasses = null;
  }
}