Edit in JSFiddle

Result
JavaScript
HTML

$(document).ready(function () {
                $("#entireDiv").click(function () {
                    $(".targetDiv").css({ 'color': 'red', 'background-color': 'orange' });
                });
                $("#children").click(function () {
                    $(".targetDiv").children().css({ 'color': 'red', 'background-color': 'orange' });
                });
                $("#reset").click(function () {
                    location.reload();
                });
            });

 <html>
        <head>
        <title>children</title>
        </head>
        <body>
        <div class="targetDiv">This is <em>99codingexamples</em></div>
        <div class="targetDiv">I love <b>jQuery</b></div><br /><br />
        <input type="button" id="entireDiv" value="Entire Div" />
        <input type="button" id="children" value="children()"/>
        <input type="button" id="reset" value="Reset" />
        </body>
        </html>