PHP “Cannot modify header information” error wont go away.
Question
I am getting the following error “Warning: Cannot modify header information - headers already sent by”, and the answers in this question are not solving this problem.
Could anybody please help me?
This is my code.
main_login
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Untitled Page</title>
</head>
<body>
<form name="form1" method="post" action="checklogin.php">
<table style="width:300px;border:0;text-align:center;background-color:#CCCCCC">
<tr>
<td>
<table style="width:100%;background-color:#FFFFFF;border:0;">
<tr>
<td colspan="3"><strong>Member Login </strong></td>
</tr>
<tr>
<td style="width:78px">Username</td>
<td style="width:6px">:</td>
<td style="width:294px"><input name="myusername" type="text" id="myusername"></td>
</tr>
<tr>
<td>Password</td>
<td>:</td>
<td><input name="mypassword" type="text" id="mypassword"></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td><input type="submit" name="Submit" value="Login"></td>
</tr>
</table>
</td>
</tr>
</table>
</form>
</body>
</html>
checkLogin.php
<?php
$dbhost = 'localhost';
$dbuser = 'myuse';
$dbpass = 'myPassword';
$dbname = 'myDbName';
// This is an example opendb.php
$conn = mysql_connect($dbhost, $dbuser, $dbpass) or die ('Error connecting to mysql');
mysql_select_db($dbname);
// username and password sent from form
$myusername=$_POST['myusername'];
$mypassword=$_POST['mypassword'];
// To protect MySQL injection (more detail about MySQL injection)
$myusername = stripslashes($myusername);
$mypassword = stripslashes($mypassword);
$myusername = mysql_real_escape_string($myusername);
$mypassword = mysql_real_escape_string($mypassword);
$sql="SELECT * FROM myTable WHERE username='$myusername' and password='$mypassword'";
$result=mysql_query($sql);
// Mysql_num_row is counting table row
$count=mysql_num_rows($result);
// If result matched $myusername and $mypassword, table row must be 1 row
if($count==1){
// Register $myusername, $mypassword and redirect to file "login_success.php"
$_SESSION['myusername'] = $myusername;
$_SESSION['mypassword'] = $mypassword;
header("location:login_success.php");
}
else {
echo "Wrong Username or Password";
}
?>
login_success.php
<?php
session_start();
if(!session_is_registered(myusername)){
header("location:main_login.php");
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
// Check if session is not registered , redirect back to main page. // Put this
code in first line of web page.
<html>
<body>
Login Successful
</body>
</html>
This is the error
Warning: Cannot modify header information - headers already sent by (output started at /home/latabla1/public_html/MenuSemanal/checklogin.php:1) in /home/latabla1/public_html/MenuSemanal/checklogin.php on line 34.
The connection to the database is fine as when I type wrong login details it goes to echo "Wrong Username or Password";, and I've checked the white spaces, but I cant find what is wrong.
Please help, I have been one whole day trying to fix this.
1 answers
solution1
2 ACCPTED 2011-05-08 10:21:53
Make sure checkLogin.php is not stored as a Unicode file (which would include a leading Byte Order Mark).
When using header , there must have been no data yet sent to the browser (as explained on the manual page).
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