Problemer med document.execCommand()

Jeg har lavet en WYSIWUG editor, men kan ikke submitte daten, den sletter det bare.


<div style="{text-align:left; width:400px; background-color: buttonface;}">
<img unselectable="on" src="gfx/Bold.gif" onclick="document.execCommand('bold');" />
<img unselectable="on" src="gfx/Italic.gif" onclick="document.execCommand('italic');" />
<img unselectable="on" src="gfx/Underline.gif" onclick="document.execCommand('underline');" />

</div>
<span id="tekst" contentEditable="true" style="{text-align:left; width:400px; height:75px; border:buttonface 1px solid;}">
</span>


<BUTTON UNSELECTABLE TITLE="Submit"
onclick='tekst.value=oDiv.innerHTML;this.form.submit();'>
Submit</BUTTON>
        <input name="tekst" type="hidden" id="tekst" value="tekst">