<div class="tdbd" id="Layer5" style="position:absolute; left:450px; top:20px; width:190px; height:120; z-index:10;">
<form name="form3" id="form3">
<input name=eingabe value="test">
</form>
</div>
<script language="JavaScript">
alert (document.Layer5.document.form3.eingabe.value);
alert (document.layers['Layer5'].document.forms['form3'].eingabe.value);
</script>
...funzt doch ;)