[RESOLVED] Use a Variable Before It's Defined

Pooptart

Okay heres the issue im having.
Take a look at THIS PAGE.
Under where it has the Black Header image, there's supposed to be another image.

In My Code, I have:

  <tr> 
    <td height="100" bgcolor="#FFFFFF" valign="top">
    	<center><?php echo "$headerpic"; ?></center>
	</td>
  </tr>

and later in the page, I have:

<?php $headerpic = "<img src=\"images/main.jpg\" width=\"760\" height=\"100\">"; ?>

The reason why I dont just put the image location where it should be with plain html, is because the page was cluttered with many include's and whatnot, so im trying to just make one header, one body, and one footer include. The reason why i'm defining it later, is because the define part is in the body, and I need the header of the page to correspond with the page its showing.

In other words, for every page I have, there is its own header that goes along with it. And I need them to correspond.

Help? 😃

NogDog

A few options:

Change the sequence of things in the script so that the variable is defined before you try to use it.
Put your variable definitions into a separate file and include()/require() that file at the start of your script.
Define a function instead of a variable to do it, as function definitions can appear after the points where they are called (as long as the function definition is not within a conditional block of some kind):
```
<?php
echo hello();

// later on . . .
function hello()
{
   return("Hello, World!");
}
?>
```
4. Create a function to define the variable in a global scope (or as a constant), call the function, and then use the values:
```
<?php
defineVars();
echo $foo;
echo BAR;

// later . . .
function defineVars()
{
   global $foo;
   $foo = 'Hello, ';
   define('BAR', 'World!');
}
```

Pooptart

Okay, I understand what your saying , but I dont think you Understand what I'm saying.

Heres a snippet of the full page:

<!-- ------------------------------------------------- -->
  <tr> 
    <td height="100" bgcolor="#FFFFFF" valign="top">
    	<center><?php echo "$headerpic"; ?></center>
	</td>
  </tr>
<!-- ------------------------------------------------- -->

<tr> 
      	<td class="forTexts" style="padding:10"><h2>Recent News</h2><br>
          <?php $headerpic = "<img src=\"images/main.jpg\" width=\"760\" height=\"100\">"; ?>
		  <?php require 'config.php'; ?>

Where in the first section, I am trying to load the pic, and in the second section, it is defining the variable as the path for the pic.

What I WOULD do is require the config.php in the first section, where the variable would be defined in the file, but the thing is, the bottom section will later be put into a seperate file as the top section, hence why I need it to be defined "later".

Is there a way to like.. skip that php code int he top section, then come back to it when the variable is defined?

NogDog

I often do something like this.

include.php:

<?php
// output start of page:
function head($title)
{
?>
<html>
<head>
<title><?php echo $title; ?></title>
</head>
<body>
<?php
}

// output end of page:
function foot($title)
{
   echo "<p>This is the end of <strong>$title</strong>.</p>\n";
   echo "</body>\n</html>";
}
?>

some_page.php:

<?php
require_once "include.php";
$title = "This is a test";
head($title);  // outputs start of page, including $test value in <title>
?>

<!-- start main content of page -->
<h1><?php echo $title; ?></h1>
<p>This is the main body of the page.</p>

<?php
foot($title);  // outputs the end of the page
?>

Pooptart

Yeah, but you defined your variables before you used them?

Im guessing its not possible to define a variable after its used, then go back?

Pooptart

Okay I figured out a way that I can do this.

In the php for the first section, I can do a bunch of if/elseif's.
If it is on page.php then show this image
Else, if it is on page2.php then show THIS image..
and so on.

So how do i say "if it is on page.php"?

NogDog

if(basename($_SERVER['PHP_SELF']) == 'page.php') {

Piranha

Note that it would be better to separate the HTML from PHP. Of course you can use variables from PHP, but just to echo. Something like this:

Do everything in php, error checking, insert into database, get from database, handle variables and so on.
Send all headers.
HTML for headers, body, footer.

Pooptart

Thanks, this worked.

Now.. when I learn how to include Vars in the URL, would i just do like this:

if(basename($_SERVER['PHP_SELF']) == 'page.php?var=definition') {

FusionComputers

To retrieve vars that are in the URL, use the superglobal array $_GET['var'].

if you want to include more than one, the URL would look like page.php?var=definition&var2=this

Then you would use
$GET['var'];
$GET['var2'];

The variables can be called anything you want, as long as they adhere to PHPs variable naming conventions.

Pooptart

Okay so If I did something like:

if(basename($_SERVER['PHP_SELF']) == 'index.php?category=SpecialEffect') { $headerpic = $_GET['category'] . '.jpg'; }

then it would work?
And what if the URL contained more than just one var, like

?category=SpecialEffect&orderby=Name&ordertype=Desc

but I only cared about the first part.. would the whole Basename thing screw up and not show anything at all?

Piranha

Try it out to understand how it works.

// Test the row below on several URLs with and without variables.
echo $_SERVER['PHP_SELF'];

// Then you can test to echo variables in the GET array
echo $_GET['varname'];

Of course, you should read the manual pages about predefinded variables, register globals and variables from outside PHP to get a better understanding.

Don't get me wrong. It is good that you want to know and that you ask, but it is even better to first test and look for answers. Your first question was a good one since it is hard to find an answer if you don't know what to search, but your last one was bad since all the clues was in the post above. Of course, it is not always easy to understand the manual, if that is the case please feel free to ask about the rows you don't understand.

Pooptart

Okay. I read it over like 5 times through and I understand, I think.

Weedpacket

Instead of basename, parse_url would be a bit more flexible.

Pooptart

			<?php
            if(basename($_SERVER['PHP_SELF']) == 'index.php') { $headerpic = 'main.jpg'; }
			elseif(basename($_SERVER['PHP_SELF']) == 'submit.php') { $headrpic = 'main.jpg'; }
			elseif(basename($_SERVER['PHP_SELF']) == 'submit_acidalia.php') { $headerpic = 'acidalia.jpg'; }
			else $headerpic = 'main.jpg';
			echo $headerpic
			?>

Why doesnt that work? Am I using the elseif's wrong?

Oh it was a typo.

bradgrafelman

EDIT: So, does that resolve your issue? If so, don't forget to mark this thread resolved.

Pooptart

Resolved.