here is some solution for your problem, you can modify as per your requirements..
$("#add").click(function () {
$("#printArea").css("display","block");
});
<div id="mainContent" style="float:left; width:10%; border-style:solid; border-radius:5px; padding:10px; margin-top:35px;"></div>
<div id="printArea" style="float: left; border-width: 3px; border-style: solid; border-radius: 5px; margin-left: 5px; margin-top: 35px; display:none;"></div>
let me know anything else you want..