[solved] How can i get FCKeditor value from javascript

Hello,

I draw a FCKeditor field with php5:

    $oFCKeditor = new FCKeditor($name);
    $oFCKeditor -> Width  = $width;
    $oFCKeditor -> Height = $height;
    $oFCKeditor -> ToolbarSet = 'Default';
    $oFCKeditor -> BasePath   = HTTP_SERVER . DIR_WS_ADMIN . 'FCKeditor/';
    $oFCKeditor -> Value = $text;
    $field = $oFCKeditor->Create($name);

I'd like to get the FCKeditor's field value with javascript. I tried this: document.getElementById('my_id').value but i got old data and not edited data.
I need this in order to check data before saving.

How can i get this value with javascript ?

Thanks for help