var priorStyle = "";

function rollon() {
  if (event.srcElement.tagName == "A") {
    priorStyle = event.srcElement.style.color;
    event.srcElement.style.color = "#FDF511";
    event.srcElement.onmouseout = rolloff;
  }
}

function rolloff() {
    //event.srcElement.style.color = "#FFFFFF";
    event.srcElement.style.color = priorStyle;
}

document.onmouseover = rollon;