Edit in JSFiddle

$(document).ready(function() {
    setTimeout(function() {
        $(".content").fadeOut(1500);
    }, 3000);

    $('#btnReset').click(function() {
        $(".content").show();
        setTimeout(function() {
            $(".content").fadeOut(1500);
        }, 3000);
    });
});

<input type="button" id="btnReset" Value=" Run Demo Again!!" />
<br/><br/>
<div class="content">  Hello, I will disappear in 3 seconds! </div>