Result

jQuery

$(document).ready(function() {
    $(".nav li").hover(function() {
        
        $(this).find("div").stop()
         //liにマウスホバーするとdivを探して210pxアニメーション移動させ、display:block;に変える
        .animate({left: "210", opacity: 1}, "fast").css("display", "block")
    }, function() {
         //div要素を戻す
        $(this).find("div").stop().animate({left: "0", opacity: 0}, "fast")
    });
});

css

.nav {/*リスト全体*/
    float: left;
    margin: 130px 0 0;
    padding: 0;
    width: 200px;
    list-style: none;
    border-bottom: 1px solid #3373a9;
    border-top: 1px solid #003867;
}
.nav li {
    position: relative;
    float: left;
    margin: 0;
    padding: 0;
}
.nav li a{
    border-top: 1px solid #3373a9;
    border-bottom: 1px solid #003867;
    padding: 10px 10px 10px 25px;
    display: block;
    color: #fff;
    text-decoration: none;
    width: 165px;
    background: #005094;
    position: relative;
    z-index: 2;
}

.nav li a:hover {
    background-color: #004c8d;
    border-top: 1px solid #1a4c76;
}

.nav li div {/*ツールチップ*/
    display: none;
    position: absolute;
    top: 2px;
    left: 0;
    width: 225px;
    font-size: 11px;
}

.nav li div p {/*ツールチップ内のテキスト*/
    margin: 7px 0;
    line-height: 1.6em;
    padding: 2px 5px 2px 30px;
        background: #fff;
}

html

<ul class="nav">
<li>
    <a href="#">List 01</a>
    <div><p>List 01 tooltip</p></div>
</li>
<li>
    <a href="#">List 02</a>
    <div><p>List 02 tooltip</p></div>
</li>
<li>
    <a href="#">List 03</a>
    <div><p>List 03 tooltip</p></div>
</li>
</ul>

via

www.­sohtanaka.­com

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