Edit in JSFiddle

 $(document).ready(function () {
                $("#NameButton").click(function () {
                    var text = $(".para").html();
                    alert(text);
                });
            });

<html>
        <head>
        <title>HTML</title>
        </head>
        <body>
        <p class="para">This is html in jquery</p>
        <p class="para">Hello World !!</p>
        <input type ="button" id="NameButton" value="click" />
        </body>
        </html>