Edit in JSFiddle

$(function () {
    $("#btn_hide").click(function () {
        $("div>span").hide();
    });

    $("#btn_show").click(function () {
        $("div>span").show();
    });

    $("#btn_toggle").click(function () {
        $("div>span").toggle();
    });
});

<div>
    <input type="button" id="btn_hide" value="hide" />
    <input type="button" id="btn_show" value="show" />
    <input type="button" id="btn_toggle" value="toggle" />
</div>
<div>
    <span>QQ</span>
</div>