var haystackText = "";
function findMyText(needle, replacement) {
     if (haystackText.length == 0) {
          haystackText = document.getElementById("haystack").innerHTML;
     }
     var match = new RegExp(needle, "ig");     
     var replaced = "";
     if (replacement.length > 0) {
          replaced = haystackText.replace(match, replacement);
     }
     else {
          var boldText = "<div style=\"background-color: yellow; display: inline; font-weight: bold;\">" + needle + "</div>";
          replaced = haystackText.replace(match, boldText);
     }
     document.getElementById("haystack").innerHTML = replaced;
}