/* Wrapper function - split search text into separate phrases and words */
function highlightSearchTerms(searchText)
{
  if (!document.body || typeof(document.body.innerHTML) == "undefined") return false;
  if ( typeof(searchText) == "undefined") {
    searchText = getParameter("srch");
    // alert("Search String = [" + searchText + "]");
  }
  var bodyText = document.body.innerHTML;
  var searchArray = searchText.split(" ");
  for (var i = 0; i < searchArray.length; i++) {
    // alert("Highlight word = [" + searchArray[i] + "]");
    bodyText = doHighlight(bodyText, searchArray[i]);
  }
  document.body.innerHTML = bodyText;
  return true;
}

/* Highlights a text string by adding HTML tags before and after the search term. */
function doHighlight(bodyText, searchTerm)
{
  const highlightStartTag = "<font style='background-color:yellow;'>";
  const highlightEndTag = "</font>";
  var newText = "";
  var i = -1;
  var lcSearchTerm = searchTerm.toLowerCase();
  var lcBodyText = bodyText.toLowerCase();

  while (bodyText.length > 0) {
    i = lcBodyText.indexOf(lcSearchTerm, i+1);
    if (i < 0) {
      newText += bodyText;
      bodyText = "";
    } else {
      // skip anything inside an HTML tag
      if (bodyText.lastIndexOf(">", i) >= bodyText.lastIndexOf("<", i)) {
        // skip anything inside a <script> block
        if (lcBodyText.lastIndexOf("/script>", i) >= lcBodyText.lastIndexOf("<script", i)) {
          newText += bodyText.substring(0, i) + highlightStartTag + bodyText.substr(i, searchTerm.length) + highlightEndTag;
          bodyText = bodyText.substr(i + searchTerm.length);
          lcBodyText = bodyText.toLowerCase();
          i = -1;
        }
      }
    }
  }
  return newText;
}

/* Get URL parameter */
function getParameter(paramName) {
  var currentUrl = window.location.search;
  var strBegin = currentUrl.indexOf(paramName) + (paramName.length+1);
  var strEnd = currentUrl.indexOf("&",strBegin);
  if (strEnd==-1) strEnd = currentUrl.length;
  var paramValue = unescape( currentUrl.substring(strBegin,strEnd) );
  while (paramValue.indexOf("+") > 1 ) paramValue = paramValue.replace("+", " ");
  return paramValue;
}