jQuery.extend({
    highlight: function(node, re, nodeName, className)
    {
        if (node.nodeType === 3)
        {
            var match = node.data.match(re);
            if (match)
            {
                var highlight = document.createElement(nodeName || 'span');
                highlight.className = className || 'highlight';
                var wordNode = node.splitText(match.index);
                wordNode.splitText(match[0].length);
                var wordClone = wordNode.cloneNode(true);
                highlight.appendChild(wordClone);
                wordNode.parentNode.replaceChild(highlight, wordNode);
                return 1; //skip added node in parent
            }
        } else if ((node.nodeType === 1 && node.childNodes) && // only element nodes that have children
                !/(script|style)/i.test(node.tagName) && // ignore script and style nodes
                !(node.tagName === nodeName.toUpperCase() && node.className === className))
        { // skip if already highlighted
            for (var i = 0; i < node.childNodes.length; i++)
            {
                i += jQuery.highlight(node.childNodes[i], re, nodeName, className);
            }
        }
        return 0;
    }
});

jQuery.fn.unhighlight = function(options)
{
    var settings = { className: 'highlight', element: 'span' };
    jQuery.extend(settings, options);

    return this.find(settings.element + "." + settings.className).each(function()
    {
        var parent = this.parentNode;
        parent.replaceChild(this.firstChild, this);
        parent.normalize();
    }).end();
};

jQuery.fn.highlight = function(words, options)
{
    var settings = { className: 'highlight', element: 'span', caseSensitive: false, wordsOnly: false };
    jQuery.extend(settings, options);

    if (words.constructor === String)
    {
        words = [words];
    }

    var flag = settings.caseSensitive ? "" : "i";
    var pattern = "(" + words.join("|") + ")";
    if (settings.wordsOnly)
    {
        pattern = "\\b" + pattern + "\\b";
    }
    var re = new RegExp(pattern, flag);

    return this.each(function()
    {
        jQuery.highlight(this, re, settings.element, settings.className);
    });
};