$.expr[':'].icontains = function(a, i, m) {
    return jQuery(a).text().toUpperCase()
        .indexOf(m[3].toUpperCase()) >= 0;
};

$("td:icontains('" + search + "')").html(function(_, html) {
    var regex = new RegExp(search, 'gi');

    return html.replace(regex, '<span style="color: red;">$1</span>');
});