Cannot Modify Header Information

[MrFish]

I'm trying to use ajax to log in users, but I get this error message.

Warning: Cannot modify header information - headers already sent by (output started at /home/mandala/public_html/includes/loginhandler.php:20) in /home/mandala/public_html/includes/loginhandler.php on line 22Warning: Cannot modify header information - headers already sent by (output started at /home/mandala/public_html/includes/loginhandler.php:20) in /home/mandala/public_html/includes/loginhandler.php on line 23

The Login handler code is.

<?	session_start();		$con = mysql_connect("localhost", "username", "password") or die(mysql_error());	mysql_select_db("mandala_maindb");		$username = mysql_real_escape_string($username);	$password = mysql_real_escape_string($password);		$query="SELECT * FROM users WHERE username ='$username'";	$run = mysql_query($query);	$results = mysql_affected_rows();		if($results!=1){		//The username doesn't exist		echo 'username false';		return false;	}		$query="SELECT * FROM users WHERE username='$username' AND password='$password'";	$run = mysql_query($query);	$results = mysql_affected_rows();		if($results==1){		//login success		echo 'login true';		$_SESSION["username"] = $username;		setCookie("username", $username, time()+60*60*24*30,'/');		setCookie("password", $password, time()+60*60*24*30,'/');	} else {		echo 'login false';		return false;	}?>

[Guest FirefoxRocks]

http://w3schools.invisionzone.com/index.ph...ost&p=96607

[Ingolme]

You can't set a cookie after writing anything to the page (using echo or putting HTML before the cookie)

[MrFish]

Yes but I thought with ajax there was a way to set a cookie.

[Ingolme]

If you're using AJAX, set the cookie with Javascript (for more details, check the W3Schools Javascript tutorial). You cannot set a cookie after outputting content.

[justsomeguy]

Using ajax doesn't change the rules for PHP. Just echo "login true" after you set the cookie, not before.