Hi lavanya,
You have to do something like below.
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript">
$(function () {
$('#txtFirstName').focus();
$('.Validate').on('blur', function (elements) {
var element = $(this)[0];
if (element.value == "") {
alert("Required!");
}
else {
//do your stuff.
}
});
});
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<table>
<tr>
<td align="right">
First Name:
</td>
<td>
<input name="txtFirstName" type="text" id="txtFirstName" class="Validate" placeholder="First Name" />
</td>
</tr>
<tr>
<td align="right">
Last Name:
</td>
<td>
<input name="txtLastName" type="text" id="txtLastName" class="Validate" placeholder="Last Name" />
</td>
</tr>
<tr>
<td align="right">
Gender:
</td>
<td>
<input name="txtGender" type="text" id="txtGender" class="Validate" placeholder="Gender" />
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
Demo
