$.fn.highlightText = function(text, className) {
  function highlight(node) {
    if (node.nodeType == 3) { // Node.TEXT_NODE
      var val = node.nodeValue;
      var pos = val.toLowerCase().indexOf(text);
      if (pos >= 0 && !$.className.has(node.parentNode, className)) {
        var span = document.createElement("span");
        span.className = className;
        span.appendChild(document.createTextNode(val.substr(pos, text.length)));
        node.parentNode.insertBefore(span, node.parentNode.insertBefore(
          document.createTextNode(val.substr(pos + text.length)),
            node.nextSibling));
        node.nodeValue = val.substr(0, pos);
      }
    } else if (!$(node).is("button, select, textarea")) {
      $.each(node.childNodes, function() { highlight(this) });
    }
  }
  return this.each(function() { highlight(this) });
}

$(document).ready(function() {
  var elems = $(".searchable");
  if (!elems.length) return;

  function getSearchTerms(url) {
    if (url.indexOf("?") == -1) return [];
    var params = url.substr(url.indexOf("?") + 1).split("&");
    for (var p in params) {
      var param = params[p].split("=");
      if (param.length < 2) continue;
      if (param[0] == "q" || param[0] == "p") { // q= for Google, p= for Yahoo
        var query = decodeURIComponent(param[1].replace(/\+/g, " "));
        if (query[0] == "!") query = query.slice(1);
        var terms = [];
        $.each(query.split(/(".*?")|('.*?')|(\s+)/), function() {
          term = this.replace(/^\s+$/, "");
          if (term.length) {
            terms.push(term.replace(/^['"]/, "").replace(/['"]$/, ""));
          }
        });
        return terms;
      }
    }
    return [];
  }

  var terms = getSearchTerms(document.URL);
  if (!terms.length) terms = getSearchTerms(document.referrer);
  $.each(terms, function() {
    elems.highlightText(this.toLowerCase(), "searchword");
  });
});