document.write('<form action="cklogin.php" method="post">通行证：用户<input name="txtUserName" type="text" /> 密码<input name="txtPassword" type="password" /><input name="txtCode" type="hidden" value="__KAicn"/> 验证码<input name="txtSign" type="text" class="sign"/> <img  id="seccode"  name="seccode" class="codeimg" src="seccode.php" onclick="this.src=\'seccode.php?update=\' + Math.random()"/><input type="image" class="img" src="style/images/login_submit.gif" /><a href="http://bbs.kaicn.com/register.php" target="_blank"><img src="style/images/login_reg.gif" class="img" /></a></form>');document.getElementById("seccode").src ='seccode.php?update=' + Math.random();