PHP and MySQL echo string only in certain conditions

Question

I am trying to use a php script to only show a link, when a "user" in a MySQL table is "logged in". What is wrong with the php code which I have tried? Mine is here below:

<? 
session_start();
if(!session_is_registered(myusername)){
header("location:main_login.php");
}

?>

<html>
<head>
require_once(checklogin.php)
</head>
<body>

<?php
if($myusername == "admin");
echo "<a href="test.html"> Click Me! </a>";
?>

</body>
</html>

The $myusername variable comes from the file below which checks the username from a form (on another page) against the mysql table and opens a session.

<?php
ob_start();
$host="-----";// Mysql username 
$password="-----"; // Mysql password 
$db_name="-------"; // Database name 
$tbl_name="-------"; // Table name 

// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect"); 
mysql_select_db("$db_name")or die("cannot select DB");

// Define $myusername and $mypassword 
$myusername=$_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 $tbl_name WHERE username='$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_register("myusername");
session_register("mypassword"); 
header("location:login_success.php");
}
else {
echo "Wrong Username or Password";
}

ob_end_flush();
?>

So to repeat my question: What exactly is wrong with this block of code

if($myusername == "admin");
echo "<a href="test.html"> Click Me! </a>";
?>

which should recognize the user and display the link

To Saiyam Patel: What is happening is "Parse error: syntax error, unexpected T_STRING, expecting ',' or ';' in /home/a5994084/public_html/login_success.php on line 19" — user1239304
– user1239304, Commented Mar 2, 2012 at 4:01
place test.html in single quotes like this ('test.html') not like this ("test.html") — OM The Eternity
– OM The Eternity, Commented Mar 2, 2012 at 4:11

Michael Berkowski · Accepted Answer · 2012-03-02 04:10:30Z

2

The cause of the syntax error is a stray ; after the if statement. It should be removed.

if($myusername == "admin");
//-----------------------^^
// Error here -- remove that semicolon!

There are some other issues here, like the unquoted value in session_register(), which should be surrounded in quotes:

session_start();
if(!session_is_registered(myusername)){
//-----------------------^^^^^^^^^^^^^
header("location:main_login.php");
}

However, the use of session_register() is not recommended. The proper modern way to set session variables is by using the $_SESSION superglobal array. (see the deprecation notices in the PHP docs)

// Set a variable
session_start();
$myusername = "admin";
$_SESSION['myusername'] = $myusername;

// Get a variable
// Always call session_start() at the beginning of the script
echo $_SESSION['myusername'];
// admin

edited Mar 2, 2012 at 4:10

answered Mar 2, 2012 at 4:03

Michael Berkowski

271k47 gold badges450 silver badges395 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

user1239304 Over a year ago

Michael, thank you for the help. I have the semicolon in my code and it still gives me the syntax error. Any idea why? Thanks

kingdaemon Over a year ago

also in the first file, he also has semicolon after if statement

user1239304 Over a year ago

Thanks again for the extra information, instead of setting the variable in this script, shouldn't the require_once allow me to call a variable from that script?

Michael Berkowski Over a year ago

@user1239304 As long as the variable set in the included file via require_once() is at global scope, it will be available to the script which included it. But if you want the value to persist across a page load, you will need to store it in $_SESSION

Costique · Accepted Answer · 2012-03-02 05:00:43Z

1

try like this

<?php
    if($myusername == "admin")
    echo "<a href='test.html'> Click Me! </a>";
?>

when you start the string with double inverted coma(") you must have to use single inverted coma(') in that statement if parser found another double inverted coma (") it will consider as a end of string

may be this issue

edited Mar 2, 2012 at 5:00

Costique

23.7k4 gold badges78 silver badges79 bronze badges

answered Mar 2, 2012 at 4:12

Saiyam Patel

1,1519 silver badges18 bronze badges

1 Comment

user1239304 Over a year ago

This fixed it! Thanks! But the only problem is that the link displays for every user... Oh well, back to the drawing board thank you for the answer!

Naveen Kumar · Accepted Answer · 2012-03-02 04:46:31Z

1

Try this

<?php
if($myusername == "admin")  // semicolon removed
{ 
// use single quotes for href or escape double quotes
echo "<a href='test.html'> Click Me! </a>"; 
}
?

edited Mar 2, 2012 at 4:46

answered Mar 2, 2012 at 4:29

Naveen Kumar

4,6011 gold badge20 silver badges39 bronze badges

Comments

OM The Eternity · Accepted Answer · 2012-03-02 04:16:13Z

0

place test.html in single quotes like this ('test.html') not like this ("test.html")

answered Mar 2, 2012 at 4:16

OM The Eternity

16.2k44 gold badges127 silver badges187 bronze badges

Comments

cool.ernest.7 · Accepted Answer · 2012-03-02 04:24:18Z

0

There are two problems. if($myusername == "admin"); // remove this semicolon after if. And echo " Click Me! "; // remove the double quotes around test.html

answered Mar 2, 2012 at 4:24

cool.ernest.7

936 bronze badges

Collectives™ on Stack Overflow

PHP and MySQL echo string only in certain conditions

5 Answers 5

4 Comments

1 Comment

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

4 Comments

1 Comment

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related