PHP Warning : Cannot modify header information - headers already sent by

maco · 11-09-2005 12:03AM #1

Hi all,

I kept getting this error message whenever I tried to use Header() function.

Any idea what this error all about ?

Thanks . . .

K!LL!@N · 11-09-2005 12:10AM

You can't output any html before you call the function.
Post up the piece of code and i'll show you where the problem is.

Killian

maco · 11-09-2005 12:23AM

Thanks Killian,

Here is the code; Sorry it's a bit long . . .

<table width="800" align="center" bordercolor="#CCCCCC">
<tr bgcolor="#00CC00">
<td colspan="3"> <div align="right"><font color="#FFFFFF" size="1" face="Georgia, Times New Roman, Times, serif">    <font face="Arial, Helvetica, sans-serif">Help  /  Site
Map / Contacts   </font></font></div></td>
</tr>
<tr bgcolor="#FFFFFF">
<td colspan="3"><font color="#CCCCCC" size="1">g</font><font size="1"><br>
<font color="#666699" size="6">xxxx/ Main</font><br>
<font color="#CCCCCC">.</font></font></td>
</tr>
<tr bgcolor="#00CC00">
<td height="30" colspan="3"> <div align="center"><font color="#999999" size="7" face="Georgia, Times New Roman, Times, serif"><font color="#336633" size="3"><font color="#999999" size="7" face="Georgia, Times New Roman, Times, serif"><font color="#336633" size="3"></font></font><font color="#FFFFFF">   <font size="2" face="Arial, Helvetica, sans-serif">Home  :  Services  :
Shopping  : Organisation   : On Sale
:  Bulletin : <font size="7" face="Georgia, Times New Roman, Times, serif"><font size="3"><font size="2" face="Arial, Helvetica, sans-serif">
Advance Search </font></font></font> :  List or Edit Site
</font></font><font color="#FFFFFF" size="7" face="Georgia, Times New Roman, Times, serif"><font size="3"><font size="2" face="Arial, Helvetica, sans-serif">:</font></font></font><font color="#FFFFFF" size="2" face="Arial, Helvetica, sans-serif">
</font><font color="#999999" size="7" face="Georgia, Times New Roman, Times, serif"><font color="#336633" size="3"><font color="#FFFFFF"><font size="2" face="Arial, Helvetica, sans-serif">
Site Promotion </font></font><font color="#FFFFFF" size="7" face="Georgia, Times New Roman, Times, serif"><font size="3"><font size="2" face="Arial, Helvetica, sans-serif"> </font></font></font><font color="#FFFFFF" size="2" face="Arial, Helvetica, sans-serif">
</font></font></font></font></font></div></td>
</tr>
<tr align="center" valign="middle">
<td colspan="3"><div align="left"><font color="#00CC00" size="1"> <font face="Arial, Helvetica, sans-serif">  >
Main > Home > </font></font></div></td>
</tr>
<tr align="center" valign="middle">
<td colspan="3"><font color="#FFFFFF" size="1">.</font><font size="1"><br>
</font><font size="3"><font color="#009900" face="Georgia, Times New Roman, Times, serif">         </font></font><font color="#006600" face="Georgia, Times New Roman, Times, serif"> </font><br>
<font size="2">    </font> <div align="center"><font color="#6666FF" size="2" face="Arial, Helvetica, sans-serif"><strong><font size="1"><br>
</font></strong><font size="1"> </font></font></div></td>
</tr>
<tr>
<td width="150" rowspan="6" align="center" valign="top" background="images/bgr.png" bgcolor="#FFFFFF">
<div align="center"><font color="#999999" size="7" face="Georgia, Times New Roman, Times, serif"><font color="#336633" size="3"><font color="#666666" size="2" face="Arial, Helvetica, sans-serif">
</font></font></font></div>
<br> </td>
<td bgcolor="#FFFFFF"> <div align="center"><font color="#6666FF" size="2" face="Arial, Helvetica, sans-serif"><strong><font color="#6666FF" size="2" face="Arial, Helvetica, sans-serif"><font size="1"><em><strong><font color="#666699" size="2">Welcome
to Town.ie</font></strong></em></font></font></strong></font></div></td>
<td width="150" rowspan="6" background="images/bgr.png" bgcolor="#FFFFFF"> </td>
</tr>
<tr>
<td bgcolor="#FFFFFF"><div align="center"><font size="1"><em><font color="#6666FF"><font face="Arial, Helvetica, sans-serif"><strong>
</strong></font></font></em></font></div></td>
</tr>
<tr>
<td height="63" align="center" valign="top"> <form action="" method="post" name="form1" onSubmit="MM_validateForm('emailid','','RisEmail','password','','R');return document.MM_returnValue">
<table width="90%">
<tr>
<td valign="top"> <div align="right"> </div></td>
<td> </td>
</tr>
<tr>
<td><div align="right"><font size="2" face="Arial, Helvetica, sans-serif">Email
ID :</font></div></td>
<td><input name="email" type="text" id="email" size="50" maxlength="50"></td>
</tr>
<tr>
<td><div align="right"><font size="2" face="Arial, Helvetica, sans-serif">Password
:</font></div></td>
<td><input name="password" type="password" id="password" size="50" maxlength="50"></td>
</tr>
<tr>
<td height="22"><font size="2" face="Arial, Helvetica, sans-serif"> </font></td>
<td> </td>
</tr>
<tr>
<td> </td>
<td><input name="logon" type="submit" id="logon" value="logon"></td>
</tr>
<tr>
<td> </td>
<td> </td>
</tr>
<tr>
<td><div align="right"> </div></td>
<td> <div align="left">
<?php

$user = "rootenq";
$host = "localhost";
$password = "xxxxxx";
$database = "yyyy";
$connection = mysql_connect($host,$user,$password)
or die ("Couldn't connect to server, please try again");
$db = mysql_select_db($database, $connection)
or die ("Couldn't connect to database, please try again");

$emailkey = '';
$pass = '';

foreach ($HTTP_POST_VARS as $key => $value )
{
If ($key == "email")
{
$emailkey = $value;
}
If ($key == "password")
{
$pass = $value;
}
}
if ($emailkey != '')
{
$query = "Select email from passpf where email = '$emailkey'";
$result = mysql_query($query)
or die ("Couldn't connect to database, please try again");
$num = mysql_num_rows($result);
if ($num == 0)
{
echo "Email ID $emailkey does not exist, please try again . . .";
}
elseif ($num == 1)
{
$query = "Select email from passpf where email = '$emailkey' and PASSWORD = $pass";
$result = mysql_query($query)
or die ("Couldn't connect to database, please try again");
$num = mysql_num_rows($result);
if ($num == 0)
{
echo "Invalid Password for Email ID $emailkey, please try again . . .";
}
elseif ($num == 1)
{
header ( "location : errordsp.php"); }
}
}
?>
</div></td>
</tr>
</table>
</form>
</td>
</tr>
<tr>
<td height="63" align="center" valign="top"> <p> </p>
<p align="center"> </p></td>
</tr>
<tr>
<td width="500" height="173" align="center" valign="top"> <p> </p>
<p align="center"> </p></td>
</tr>
<tr bgcolor="#CCCCCC">
<td height="21" bgcolor="#FFFFFF"> </td>
</tr>
<tr bgcolor="#00CC00">
<td height="18" colspan="3"> <div align="center"><font color="#006600" size="1" face="Georgia, Times New Roman, Times, serif"><font color="#FFFFFF"><font face="Arial, Helvetica, sans-serif">Help  /  Site
Map / Contacts  </font></font></font><font color="#FFFFFF" size="1" face="Arial, Helvetica, sans-serif">/  Disclaimer</font><font color="#FFFFFF" size="2" face="Arial, Helvetica, sans-serif"><br>
</font><font color="#FFFFFF" size="2" face="Geneva, Arial, Helvetica, sans-serif">
</font></div></td>
</tr>
</table>

K!LL!@N · 11-09-2005 12:31AM

Move the PHP code to the top of the file before you output any HTML.
It should be fine then.

Killian

Civilian_Target · 11-09-2005 12:35AM

Bingo. If you plan to use the header() function you must start your file with <?php as the first 5 chars, and use the function before any print (or similar) statements, or before ?>

maco · 11-09-2005 12:42AM

Sorry Killian, I have moved it up already but still the same problem ...

I used dreamweaver to create the page, does this mean I should use all PHP script to avoid this problem ?

maco · 11-09-2005 12:45AM

Sorry Civilian, not sure what you mean, I am very new to this . . .

K!LL!@N · 11-09-2005 12:56AM

[PHP]<?php

//Put whatever PHP code you want here.

//If some condition is meet then redirect the page.
if( $foo == $bar )
{
header("Location: http://www.example.com/");
exit;
}
?>

[/PHP]

No worries, Maco.

I'll try and explain it a little more.

In the above piece of code, i've shown you basically what you need to do.

Open a new file.
Open the PHP tag <?php on the first line.
There can't be anything before this, no spaces, nothing.

Put in your code for connecting to the database or anything else you like.

Then you can add your IF statement with the header() function inside that.
Use exit; after you call the header() function to prevent anything else being executed.

When you close the PHP tag, then you can output your HTML.

Hope this explains it a little better.

Killian

maco · 11-09-2005 11:51AM

Got you Killian, it worked now. Thanks you very much, spend long night yesterday just to fix that . .

To recap, Header() function must be defined before any HTLM output, for what I am doing now I need a global variable so that I can code it anywhere in my file and then use that variable later to decide where to go . . .

Thanks . . .

K!LL!@N · 11-09-2005 11:54AM

Glad you got it sorted in the end.

Killian

maco · 11-09-2005 12:24PM

Killian one last question, how do I use global variables, I ahve been looking in the net and book for sample but still cannot find a good one.

Is this possible;

<?PHP

echo $globalvariable;

?>

HTML code here ...

<?PHP

$globalvariable = "test";

?>

Thanks . . .

K!LL!@N · 11-09-2005 12:44PM

[PHP]
<?php

$myVariable = "I am a string variable, i like to be displayed on screen.";

?>



<?php

echo $myVariable;

?>
[/PHP]

Your code probably isn't working because when you try to echo the variable the first time it hasn't been initialised so there's nothing to echo out.

In my example, i've initialised $myVariable with a string value.
So when i echo it, you'll see that string outputted on the screen.

Killian

maco · 11-09-2005 01:14PM

Thanks . . . I did not realise it that easy . . . thanks a million . .

K!LL!@N · 11-09-2005 01:17PM

Killian

PHP Warning : Cannot modify header information - headers already sent by

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