JavaScript: (un)Highlighting Text #snippet

highlight.js

var TextUtil = (function() {
  return {
    highlight: function (text, words, tag) {
      // Default tag if no tag is provided
      tag = tag || 'span';

      var i, len = words.length, re;
      for (i = 0; i < len; i++) {
        // Global regex to highlight all matches
        re = new RegExp(words[i], 'g');
        if (re.test(text)) {
          text = text.replace(re, '<'+ tag +' class="highlight">$&</'+ tag +'>');
        }
      }

      return text;
    },
    unhighlight: function (text, tag) {
      // Default tag if no tag is provided
      tag = tag || 'span';
      var re = new RegExp('(<'+ tag +'.+?>|<\/'+ tag +'>)', 'g');
      return text.replace(re, '');
    }
  };
}());

element.innerHTML = TextUtil.highlight(
    element.innerHTML,                  // the text
    ['highlight', 'me', 'is', 'cool'],  // list of words or phrases to highlight
    'strong'                            // custom tag
);