一个登陆判断的源码
mysql_connect($dbhost,$dbuser,$dbpasswd) or die ("数据库连接失败");
$sql = "SELECT * FROM $ym_article_user_table WHERE username='$username'";
$result = mysql_db_query($dbname, $sql);
$objresult = mysql_fetch_object($result);
$user_password = $objresult->password;
if ($username=="" || $password==""):
echo "用户名或密码不能为空";
echo "<META HTTP-EQUIV=REFRESH CONTENT='0;URL=index.php'>";
exit;
endif;if ($user_password == ""):
echo "用户名错误";
echo "<META HTTP-EQUIV=REFRESH CONTENT='0;URL=index.php'>";
exit;
endif;if ($password != $user_password):
echo "密码错误";
echo "<META HTTP-EQUIV=REFRESH CONTENT='0;URL=index.php'>";
exit;
endif;setcookie ($cookie_name."[1]",$username,time
);echo "登录成功!";
echo "<META HTTP-EQUIV=REFRESH CONTENT='0;URL=list.php'>";exit;} // end login
mysql_connect($dbhost,$dbuser,$dbpasswd) or die ("数据库连接失败");
$sql = "SELECT * FROM $ym_article_user_table WHERE username='$username'";
$result = mysql_db_query($dbname, $sql);
$objresult = mysql_fetch_object($result);
$user_password = $objresult->password;
if ($username=="" || $password==""):
echo "用户名或密码不能为空";
echo "<META HTTP-EQUIV=REFRESH CONTENT='0;URL=index.php'>";
exit;
endif;if ($user_password == ""):
echo "用户名错误";
echo "<META HTTP-EQUIV=REFRESH CONTENT='0;URL=index.php'>";
exit;
endif;if ($password != $user_password):
echo "密码错误";
echo "<META HTTP-EQUIV=REFRESH CONTENT='0;URL=index.php'>";
exit;
endif;setcookie ($cookie_name."[1]",$username,time
);echo "登录成功!";
echo "<META HTTP-EQUIV=REFRESH CONTENT='0;URL=list.php'>";exit;} // end login
<input type="text" name="uid" >
<input type=submit name="submit">file2.php文件如下<?php
if(isset($uid) && $uid)//uid為從表單中傳過來的用戶名。
{$link=connection();
$strsql="select * from user where uid='$uid'";
$result=mysql_query($strsql,$link);
$row=mysql_fetch_row($result);
if(!$row[0])
{$strsql="select * from base_info where uid='$uid'";
$result=mysql_query($strsql,$link);
$row=mysql_fetch_row($result);
if ($row[0])
{echo "此用戶存在";}
else
{ echo "此用戶不存在";}
?>