Edit in JSFiddle

 $(document).ready(function () {
                $("#myButton").click(function () {
                    var target = $("#target");
                    $("ul").find(target).css({ 'font-size': '28px', 'font-family': 'Arial', 'color': 'Green' });
                });
            });

<html>
        <head>
        <title>find</title>
        </head>
        <body>
        <ul type="circle">
        <li>Cesc Fabregas</li>
        <li id="target">Thierry Henry</li>
        <li>Robin Van Persie</li>
        <li>Tomas Rosicky</li>
        </ul><br />
        <input type="button" id="myButton" value="Click ME"/>
        <input type="button" value="Reset" onclick="location.reload()"/>
        </body>
        </html>