Edit in JSFiddle

Result
JavaScript
HTML

$(document).ready(function () {
                var css = {
                    'color': 'Red',
                    'text-decoration': 'underline',
                    'font-size': '30px'
                }
                $("#myButton").click(function () {
                    $("#targetLi").siblings().css(css);
                });
            });

<html>
        <head>
        <title>sibling</title>
        </head>
        <body>
        <ul type="circle">
        <li>Javascript</li>
        <li id="targetLi">Jquery</li>
        <li>MVC</li>
        <li>Linq</li>
        </ul>
        <input type="button" id="myButton" value="Click ME"/>
        </body>
        </html>