[jQuery] Validation Plugin - How to Validate input="file"

[Adam]

I'm trying to validate that someone has selected a file for upload
before submitting a form.  I set the required class on the input
element, but it's not being validated.  The regular text input is
validated, however.


<form:form id="pictureform" commandName="pictureCommand"
        action="${actionURL}" method="post" enctype="multipart/form-data"
        cssClass="update">
        <div>
                <label for="title">
                        Title:
                </label>
                <form:input path="title" cssClass="required" />
        </div>

        <div>
                <label for="description">
                        Description:
                </label>
                <form:textarea path="description" />
        </div>

        <label for="image">
                Select File:
        </label>
        <input type="file" name="image" cssClass="required" />
        <input type="submit" value="Add" />
</form:form>