textarea didn't convert into tiny MCE while called in javascript

i have problem while called text area that should be convert into tiny MCE from insert.php into manage.php. please help.thx

here my code

insert.php

    <SCRIPT type="text/javascript">
    tinyMCE.init({....});   
    </SCRIPT>

    <?php
        echo '<TD>';
        echo '<textarea id=texta></textarea>';
        echo '</TD>';
    ?>

manage.php

    <SCRIPT type="text/javascript">
        $(document).ready(function() {
                $("#add").click(function() {
            $.post("insert.php",{},function(data) {
                   $("#content").html(data);
            });
            });
        });
    </SCRIPT>

when i click #add its load insert.php but the textarea inside insert.php won't change into tiny MCE editor.

You need to make sure that tinymce.init gets executed after the phph is fully loaded (you may use $(document).ready for this).