public Attr(Attr parent, params object[] sa)
{
wv.assert((sa.Length % 2) == 0);
if (parent != null)
s = parent.ToString();
for (int i = 0; i < sa.Length; i += 2)
s += String.Format(" {0}=\"{1}\"",
HttpUtility.HtmlAttributeEncode(sa[i].ToString()),
HttpUtility.HtmlAttributeEncode(sa[i+1].ToString()));
}