changing multiple elements' style independently via php

...But I still can’t change the logo background color and the body background independently. One of them has to be default, I can’t view an alternative bg with an alternative logo-bg. I created two sessions, one for the logo background:

<?php $_SESSION['logoBgColor'] = 'yellow';
if(isset($_GET['logoBgColor'])) 
    $_SESSION['logoBgColor'] = $_GET['logoBgColor'];
?>

<link href="&lt;?php bloginfo('template_url'); ?&gt;/css/logo-bg-&lt;?php echo $_SESSION['logoBgColor']; ?&gt;.css" rel="stylesheet" type="text/css" media="all" /

and one for the body background:

<?php $_SESSION['background'] = 'style';
if(isset($_GET['background'])) 
    $_SESSION['background'] = $_GET['background'];
?>

<link href="<?php bloginfo('template_url'); ?>/css/<?php echo $_SESSION['background']; ?>.css" rel="stylesheet" media="all" type="text/css" />

but as I said, when I change one of them, the other one falls back to default. How do you guys resolve that issue?

Well, you should not override the session Don’t use

<?php $_SESSION['color'] = 'red';
if(...)
</pr?>

but instead, first check if the session is set and if not, set it to red.

Well, you should not override the session Don’t use

<?php $_SESSION['color'] = 'red';
if(...)
</pr?&gt;

but instead, first check if the session is set and if not, set it to red.

So will it be something like below?

<?php if(!isset($_SESSION['color'])) {
    $_SESSION['color'] = 'red';    
} else {
    if(isset($_GET['color']))
        $_SESSION['color'] = $_GET['color'];    
}

?>

<link href="<?php bloginfo('template_directory'); ?>/css/<?php echo $_SESSION['color']; ?>.css" rel="stylesheet" media="all" type="text/css" />

Well, you should not override the session Don’t use

<?php $_SESSION['color'] = 'red';
if(...)
</pr?&gt;

but instead, first check if the session is set and if not, set it to red.

So will it be something like below?

<?php if(!isset($_SESSION['color'])) {
    $_SESSION['color'] = 'red';    
} else {
    if(isset($_GET['color']))
        $_SESSION['color'] = $_GET['color'];    
}

?>

<link href="<?php bloginfo('template_directory'); ?>/css/<?php echo $_SESSION['color']; ?>.css" rel="stylesheet" media="all" type="text/css" />

Almost. Look again at the code – what if you just set a session, but want to override the before the last session expires.

So, what does the exact code have to be? :)) Tnx for sharing your experience with me and each other guys, I appreciate it.

I could post it, but then you wouldn’t learn it as good as if you tried by yourself, right? How about, I post now just some pseudo code and you try to get it by yourself. If you still fail, I will post the solution, ok?

check if session is set
if so, check if new color is requested via get {
    if requested, set the color
    if not, 
}
if not, get default color

include css

Of course this is only one of many possible solutions

Thanks so much Wizylabs, I tested the code you posted and it can change different elements’ style seperately

I could post it, but then you wouldn’t learn it as good as if you tried by yourself, right? How about, I post now just some pseudo code and you try to get it by yourself. If you still fail, I will post the solution, ok? Pseudo code

check if session is set
if so, check if new color is requested via get {
    if requested, set the color
    if not, 
}
if not, get default color

include css

Of course this is only one of many possible solutions

And Bebel, not being a php coder and looking previous posts, it has to start with something like :

<?php if(isset($_SESSION['color'])) 
     if(isset($_GET['color'])) {
        $_SESSION['color'] = $_GET['color']; 
     }
     $_SESSION['color'] = 'red'; 
?>     
<link href="<?php bloginfo('template_directory'); ?>/css/<?php echo $_SESSION['color']; ?>.css" rel="stylesheet" type="text/css" media="all" />

Yes, it doesn’t work and it’s obvious I don’t have php experience lol

I got the point that you are not a experienced php coder, but if you want to publish a template on themeforest, you have to know some, or am I wrong? Was your theme coded by another person?

Yeah, your code does not work because you, again, override your session at every request.

<?php if(isset($_SESSION['color'])) // missing {, the syntax without { only works for ONE following line!
     if(isset($_GET['color'])) {
        // if the session is set and the color comes from the url, set it in session
        $_SESSION['color'] = $_GET['color']; 
     }
     // if the session is set, set it to red !!! PROBLEM IS HERE !!!
     $_SESSION['color'] = 'red'; 
// missing }
?>  

See the comments, where the problem is. You ALWAYS set the session to red if the session is set..

<?php if(isset($_SESSION['color'])) {
     if(isset($_GET['color'])) {
        // if the session is set and the color comes from the url, set it in session
        $_SESSION['color'] = $_GET['color']; 
     }
}else {
  if(isset($_GET['color'])) {
    $_SESSION['color'] = $_GET['color']; 
  }else {
    $_SESSION['color'] = 'red'; 
  }
}
?>  

This would be one solution. But its not pretty, so what about this one?

<?php // to at least have SOME security, don't take any variables unfiltered..

$allowed_colors = array('red', 'blue', 'green'); // add your colors...

$color = isset($_GET['color']) && isset($allowed_colors[$_GET['color']) ? $_GET['color'] : 'red'; // if the color is set via get and if it is in the allowed colors list, set the color from request, otherwise set default color (red)

$_SESSION['color'] = isset($_GET['color']) ? $color : isset($_SESSION['color']) ? $_SESSION['color'] : 'red'; // if the get var does exist, get the color from $color, otherwise renew the session, if exists, or set the color to red.
</pr?>

Please note this solution was coded in the post textarea and is NOT tested. 

I got the point that you are not a experienced php coder, but if you want to publish a template on themeforest, you have to know some, or am I wrong? Was your theme coded by another person?

Good point All my themes are coded by me. When I decided to release some WP themes, I wanted to hire a WP coder, but I couldn’t find anyone who already has at least a WP theme / site online (they were all busy) and decided to learn and do it by myself. So, now I can code html/css, WP but apparently I better to learn some php, thanks (and some jquery/js to create custom scripts would be nicer too)

Looking your code, I can say the biggest lack of the snippet I wrote is syntax. But I have a question, it works like this too:

<?php if(isset($_SESSION['color'])) {
     if(isset($_GET['color'])) {
        $_SESSION['color'] = $_GET['color']; 
     }
}else {
   $_SESSION['color'] = 'red'; 
  }
?>

And this code is “one if condition less” so it’s lighter. I couldn’t get the problem with this one? (If you stated it above sorry :))

And the final snippet you posted, thank you very much for sharing the solution, as you guess it has some syntax issues and it doesn’t work. But thanks a lot again :))

I got the point that you are not a experienced php coder, but if you want to publish a template on themeforest, you have to know some, or am I wrong? Was your theme coded by another person?

Good point All my themes are coded by me. When I decided to release some WP themes, I wanted to hire a WP coder, but I couldn’t find anyone who already has at least a WP theme / site online (they were all busy) and decided to learn and do it by myself. So, now I can code html/css, WP but apparently I better to learn some php, thanks (and some jquery/js to create custom scripts would be nicer too)

Looking your code, I can say the biggest lack of the snippet I wrote is syntax. But I have a question, it works like this too:

<?php if(isset($_SESSION['color'])) {
     if(isset($_GET['color'])) {
        $_SESSION['color'] = $_GET['color']; 
     }
}else {
   $_SESSION['color'] = 'red'; 
  }
?>

And this code is “one if condition less” so it’s lighter. I couldn’t get the problem with this one? (If you stated it above sorry :))

And the final snippet you posted, thank you very much for sharing the solution, as you guess it has some syntax issues and it doesn’t work. But thanks a lot again :))

Well, coding is nothing else than putting your logical thoughts into code. Think about what you have to do, think about what steps you have to check – first without code. Try to find holes in your thoughts and in your model, improve it step by step – thats how all begins when you start coding. After a while it will become easier and faster. But at the beginning it is good to take some time.

As I stated above in my second example, you should never take any values from an user (via get, post or generally request, ..) unfiltered. NEVER trust your users

In your code, you miss the possibility: What, if the session is not set but the user wants to change the color? Like if I don’t click on your preview link first and then change the color, but directly access http://yoursite.net/?color=blue. Thats why your code is a bit lighter than mine

For the errors: sorry, yeah, I coded it like 10 min after breakfast in the themeforest forum textarea You can try to fix it by yourself, then you will become familiar with php errors