It is very easy to do. Instead of attaching the validation engine plugin on page load we will now attach only on buttons we want to validate the form and for other buttons we will have to detatch the validation engine.
I have modified the sample available at jQuery Form Validation Example in ASP.Net
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<style type="text/css">
body
{
margin-top: 100px;
font-family: Arial;
font-size: 10pt;
}
input, select
{
width: 150px;
}
</style>
</head>
<body>
<form id="form1" runat="server">
<table border="0" cellpadding="0" cellspacing="0">
<tr>
<td>
</td>
<td>
Please fill the following Form
</td>
</tr>
<tr>
<td style="height: 40px">
</td>
</tr>
<tr>
<td>
Name:
</td>
<td>
<asp:TextBox ID="txtName" runat="server" CssClass="validate[required]" />
</td>
</tr>
<tr>
<td style="height: 40px">
</td>
</tr>
<tr>
<td>
Email:
</td>
<td>
<asp:TextBox ID="txtEmail" runat="server" CssClass="validate[required,custom[email]]" />
</td>
</tr>
<tr>
<td>
</td>
</tr>
<tr>
<td>
<asp:Button ID="btnSubmit" Text="Submit" runat="server" />
</td>
<td>
<asp:Button ID="btnCancel" Text="Cancel" runat="server" />
</td>
</tr>
</table>
</form>
<link href="ValidationEngine.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript" src="http://cdn.ucb.org.br/Scripts/formValidator/js/languages/jquery.validationEngine-en.js"
charset="utf-8"></script>
<script type="text/javascript" src="http://cdn.ucb.org.br/Scripts/formValidator/js/jquery.validationEngine.js"
charset="utf-8"></script>
<script type="text/javascript">
$(function () {
$('[id*=btnSubmit]').bind("click", function () {
$("#form1").validationEngine('attach', { promptPosition: "topRight" });
});
$('[id*=btnCancel]').bind("click", function () {
$("#form1").validationEngine('detach');
});
});
</script>
</body>
</html>