Q500 Is it possible to list all inherent properties and methods of a given object such as one used in an embed tag?

<EMBED SRC="sound.mid" NAME="mySound" MASTERSOUND AUTOSTART="false" LOOP=1 HIDDEN="true" HEIGHT=0 WIDTH=0>

<SCRIPT LANGUAGE="JavaScript"><!--
function interrogate(what) {
    var output = '';
    for (var i in what)
        output += i+ '\n';
    alert(output);
}
//--></SCRIPT>

<FORM>
<INPUT TYPE="BUTTON" onClick="interrogate(document.embeds[0])" VALUE="View">
</FORM>