Enable Submit Button in a Form

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Simple Registration Form - Enable Submit when all field have data</title>
    <!-- Latest compiled and minified CSS -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" >
<script src="http://code.jquery.com/jquery-1.11.3.min.js"></script>
    <link rel="stylesheet" href="">
    <style type="text/css">
    *{
        padding: 0;
        margin: 0;
    }
div fieldset{
    margin:

}
    </style>
</head>
<body>

    <div id="main" class="container">
    <div id="RegistrationForm" class="row form-inline ">
        <fieldset class="form-group col-md-6 col-sm-6 has-success">
            <label for="userName" class="form-control-label col-md-4 col-sm-4 col-lg-4">User Name</label>
            <input type="text" id="userName" class="form-control form-control-success col-md-8 col-sm-8 col-lg-8"/>
        </fieldset>
        <fieldset class="form-group col-md-6 col-sm-6">
            <label for="password" class="col-md-4 col-sm-4 col-lg-4">Password</label>
            <input type="passsword" id="password" class="form-control col-md-8 col-sm-8 col-lg-8"/>
        </fieldset>
        <fieldset class="form-group col-md-6 col-sm-6">
            <label for="firstName" class="col-md-4 col-sm-4 col-lg-4">First Name</label>
            <input type="text" id="firstName" class="form-control col-md-8 col-sm-8 col-lg-8"/>
        </fieldset>
        <fieldset class="form-group col-md-6 col-sm-6">
            <label for="lastName" class="col-md-4 col-sm-4 col-lg-4">Last Name</label>
            <input type="text" id="lastName" class="form-control col-md-8 col-sm-8 col-lg-8"/>
        </fieldset>
        <fieldset class="form-group col-md-6 col-sm-6">
            <label for="emailId" class="col-md-4 col-sm-4 col-lg-4">Email Id</label>
            <input type="text" id="emailId" class="form-control col-md-8 col-sm-8 col-lg-8"/>
        </fieldset>
        <fieldset class="form-group col-md-6 col-sm-6">
            <label for="confirmPassword" class="col-md-4 col-sm-4 col-lg-4">Confirm Password</label>
            <input type="passsword" id="confirmPassword" class="form-control col-md-8 col-sm-8 col-lg-8"/>
        </fieldset>
        <fieldset class="form-group col-md-6 col-sm-6">
            <label for="industry" class="col-md-4 col-sm-4 col-lg-4">industry</label>
            <input type="text" id="industry" class="form-control col-md-8 col-sm-8 col-lg-8"/>
        </fieldset>
        <fieldset class="form-group col-md-6 col-sm-6">
            <label for="city" class="col-md-4 col-sm-4 col-lg-4">City</label>
            <input type="passsword" id="city" class="form-control col-md-8 col-sm-8 col-lg-8"/>
        </fieldset>
        <div class="btn-group col-md-11 col-lg-11 col-sm-11 pull-right">
        <button class="btn btn-danger ">Cancel</button>
        <button id="register" class="btn btn-primary"  disabled="disabled">Submit</button>
</div>
    </div>

</div>
<script type="text/javascript">
    (function() {
    $('#RegistrationForm > fieldset > input').keyup(function() {

        var isAnyFieldEmpty = false; //assume all field have values
        $('#RegistrationForm > fieldset > input').each(function() {
            if ($(this).val() == '') {
                isAnyFieldEmpty = true; //oh snap got a empty field
            }
        });

        if (isAnyFieldEmpty) {
            $('#register').attr('disabled', 'disabled'); //disable submit button
        } else {
            $('#register').removeAttr('disabled'); //enable submit button
        }
    });
})()
</script>

</body>
</html>