点击超连接，为何不响应

function popmsg(msgstr)
{
  var winstr=" <table style=\"border:1 solid #FFA6CA \" width=\"241\" height=\"172\" border=\"0\" cellpadding=\"0\" cellspacing=\"0\" background=\"back.jpg\">";
      winstr+=" <tr> <td height=\"30\"> </td> </tr> <tr> <td align=\"center\"> <table width=\"90%\" height=\"110\" border=\"0\" cellpadding=\"0\" cellspacing=\"0\">";
      winstr+=" <tr> <td valign=\"top\" style=\"font-size:12px; color: blue; face: Tahoma\">"+msgstr+" </td> </tr> <tr> <td>";
  winstr+=" <a href='#' onclick=\"top.location.href='http://www.sina.com.cn'\">查看 </a> </td> </tr> </table> </td> </tr> </table>";
  oPopup.document.body.innerHTML = winstr;
  popshow();
}