SetB11
<html>
<head>
</head>
<body>
<form name="Membership_login" onsubmit="validfunction()"
method="post">
<center>
<h3>Membership form</h3>
Username: <input type="text" name="user"></br></br>
Password: <input type="password" name="pass"></br></br>
<button type="submit" value="Login">LogIn</button>
</center>
</form>
<script type="text/javascript">
function validfunction()
{
var user = document.Membership_login.user.value
var pass = document.Membership_login.pass.value
if(user ==="rohit" && pass === "rohit123")
alert("login successful")
else if(user == null || pass=="")
alert("Empty username or password field.")
else
alert("inavlid credentials.")
}
</script>
</body>
</html>