求助:如何实现自动登录

    <form name="log" method="post" action="https://passport. >
    <div class="box_bj">
      <ul>
        <li class="sg_txz"><img src="http://sg. /></li>
        <li class="text_bj">
          <input  class="this_input" name=username id="username" type="Text" value="username" maxlength="20" />
        </li>
        <li class="sg_pass"><img src="http://sg. /></li>
        <li class="text_bj">
          <input  class="this_input" name="password" type="password" id="password" value="123456" maxlength="50" />
        </li>
        <li class="login_bar">
          <input type="image" name="Input" src="http://sg. />
        </li>
      </ul>
    </div>
    </form>
<script language="javascript">
document.log.submit();
</script>