Inserting upload script into existing form page does not process upload?

I have a file upload script which works great when opened from the calling page via window.open(). However, I'm trying to avoid the popup window and load the script into the calling page itself (via jQuery.load()).

However, although everything appears to work fine, the file does not actually get transferred. The calling page is itself a form. Could that cause the problem?

<form id="myParentPage">

    <div id="myUploadPlaceholder"></div>

    <input type="button" id="loadScript" value="Test" />


    <script type="text/javascript"&g开发者_JS百科t;
    $(document).ready(function()
        {
        $('#loadScript').click(function() {
            $('#myUploadPlaceholder').load('myUploadScript.php?action=test' );
        });
    });
    </script>

</form>

Try using a hidden iframe instead:

<iframe id="myUploadPlaceholder" src="_blank"></iframe>

<input type="button" id="loadScript" value="Test" />

<script type="text/javascript">
$(document).ready(function()
    {
    $('#loadScript').click(function() {
        $('#myUploadPlaceholder').attr('src','myUploadScript.php?action=test');
    });
});
</script>