I'm testing, getting used to forms. I'm trying to make the JavaScript check the value of the and display a little message next to it if it's not filled in. Simple enough right?

```
    <script>
        function ValidateForm() {
        var x = document.forms["Form"]["fName"].value;

        If (x==null || x=="") { 
        document.getElementById("FN").innerHTML = "This field must be filled in"; }

        }
    </script>
<body>
        <form name="Form" onload="ValidateForm()">
        First Name: <input type="text" name="fName"> <p id="FN"></p>
        Last Name: <input type="text" name="sName"> <p id="SN"></p>

        </form>

</body>

```

Unfortunately, the paragrapgs "FN" and "SN" remain empty onload. I know this isn't a practical thing here since the validation wont refresh and only runs onload when the fields are bound to be empty already but I'm going to add crap in later that I already know how to use.

How can I get this to work?