Using Accordion as navigation menu

Using Accordion as navigation menu

I'm totally new to JS and i could really use some help with this.
I'm doing a navigation menu using the accordion. Everything work fine
when it follows the "header, ul, header, ul" rhythm, but when a
category doesn't have subcategories listed after it, everything messes
up.
How do i fix that? Thanks in advance.
This is my HTML structure:
        <div class="accordion">
            <h2>Category 1</h2>
            <ul>
                <li><a href="#">Subcategory 1</a></li>
                <li><a href="#">Subcategory 2</a></li>
                <li><a href="#">Subcategory 3</a></li>
                <li><a href="#">Subcategory 4</a></li>
            </ul>
            <h2>Category 2 (WITHOUT SUBCATEGORIES!!!)</h2>
            <h2>Category 3</h2>
            <ul>
                <li><a href="#">Subcategory 1</a></li>
                <li><a href="#">Subcategory 2</a></li>
            </ul>
            <h2>Category 4</h2>
            <ul>
                <li><a href="#">Subcategory 1</a></li>
                <li><a href="#">Subcategory 2</a></li>
            </ul>
        </div>
--