带有PHP网站的Ajax选项卡

I have a "little" big problem with my web application. First, I must confess, that I am not so good in english :).

I have realize very simple html+css-Tabs based on ajax (powered by jquery) and each Tab request a separate PHP-site. Every site includes min. one form with php-values and other jquery-effects/-plugins.

The primary problem is the form-view in every tab. The ajax-loaded forms were shown not complete and other form were complete blank. I locate the problem and delete PHP-code in one of some fieldsets and finaly I show this one fieldset and the rest of the form were blank.

If I use only css-based tabs and without ajax functionality the forms loaded completely.

What is the problem with ajax? I dont understand it :P

Here is a part of one of the forms:

 <form action="#" method="post" name="form_project" class="form_project mainform">
    <input type="hidden" name="uid" value="<?= issetGlobals('uid') ?>" />
    <table border="0" id="tbl-projects" cellspacing="0" cellpadding="5">
        <tr>
            <td colspan="2"><input type="checkbox" name="cb_newProject" onclick="actFieldset('#fs-newProject')" /> <label for="cb_newProject">Projekt erstellen</label></td>
        </tr><tr>
            <td>

            <fieldset id="fs-newProject" disabled="disabled"><legend>Projektverzeichnis erstellen</legend>
                <table border="0">
                    <tr>
                        <td><label for="projectName">Projektname</label></td>
                        <td><input type="text" name="projectName" value="" /></td>
                    </tr><tr>
                        <td><label for="projectManager">Projektleiter</label></td>
                        <td><select size="1" name="projectManager" id="projectManager">
                        <?php
                            foreach($DBma->getEmployees() as $value) {
                                if($value['uid'] == issetGlobals('uid'))
                                    echo '<option value="'.$value["uid"].'" selected="selected">'. convertString($value["name"]) .'</option>';
                                else
                                    echo '<option value="'.$value["uid"].'">'. convertString($value["name"]) .'</option>';
                            }
                        ?>
                            </select>
                        </td>
                    </tr>

And here the "converted" JS-Code:

$('#tabs-nav li').each(function(i) {
    $(this).click(function(event){
        event.stopPropagation();
        Tab($(this).attr('id'));
    });
});

function Tab(key){
    $('#tabs-nav li').each(function() {
        $(this).removeClass('active');
    })
    $(key).addClass('active');

    $.ajax({
        url: 'tab-content.php?tab=' + key,
        type: 'get',
        beforeSend: function() {
            $(key + '-loading').html('<img src=\'images/ajax-loader.gif\' width=\'16\' height=\'16\' alt=\'Loading\' />');
        }
    }).done(function(responseText)  {
            $(key + '-loading').html("");
            $('#tabs-content').html(responseText);
        });
}