Highlight a word with jQuery

Question

I basically need to highlight a particular word in a block of text. For example, pretend I wanted to highlight the word "dolor" in this text:

Answer 1

$(function () {
    $("#txtSearch").keyup(function (event) {
        var txt = $("#txtSearch").val()
        if (txt.length > 3) {
            $("span.hilightable").each(function (i, v) {
                v.innerHTML = v.innerText.replace(txt, "" + txt + "");
            });

        }
    });
});

Jfiddle here