I am, basically, answering the question here, but perhaps someone has another idea. You can use an onpopstate function, but I find this much simpler to deal with and cross-browser compatible, even with old browsers.

I have a drop-down select box that is populated by a database query. In this case, it has only found one relevant city. Selecting that city, which takes the user to another page, then pressing the Back button, returns the user to the page with the selection still in the selected state, which prevents it from being selected again, unless another selection is made first. So I added an onClick event to change the Selected default before leaving the page.

HTML

<div>
    <select class="DropList"  name="CitySelect" id="CitySelect"
        onchange="if(options[selectedIndex].value){location = options[selectedIndex].value}"
        onclick="GetSelect()">
        <option value="" selected>Select City</option>
        <option value="city.php?s=Montana&cn=Yellowstone&CalNav=0&c=Billings">Billings</option>
    </select>
</div>

JavaScript

<script type="text/javascript">
    function GetSelect()
    {
        document.getElementById('CitySelect').value = "";
    }
</script>