var seite = document.getElementById("seite").value;

document.write('<object type="application/x-shockwave-flash" data="/topframe.swf?seite=');
document.write(seite);
document.write('" width="1003" height="245" id="topframe" align="middle">');
document.write('<param name="allowScriptAccess" value="sameDomain" />');
document.write('<param name="movie" value="topframe.swf?seite=');
document.write(seite);
document.write('">');
document.write('<param name="quality" value="high" />');
document.write('<param name="bgcolor" value="#ffffff" />');
document.write('</object>');