catch Prev/Next buttons

andreiga

Does anyone know how can I "catch" or see if a Prev/Next browser button has been clicked?
I need this because I have many products to display on a site and to do it in on page is to big, thus I am trying to make dynamic pages. My created Prev/Next links are working perfect but when I push Prev/Next/Refresh buttons of the browser the internal variables are not updated and the whole chain of pages is broken.
If anyone has another ideea besides catching these buttons I would be very happy to hear it.

edspace

You can do this with Javascript so the page will open in fullscreen mode and the user wont see the back, forward, stop, refresh, etc.

Then again they can always pres backspace on the keyboard or just right click and press back from the context menu.

There should be no reason for your own browser buttons and if you need them it's probably because of bad design.

jerdo

What are you talking about ed? Next and Prev buttons on the page are great the forward button on the browser won't work if the surfer hasn't visited the page already. Andreiga if you could post some of your code, someone might be better able to help you.

andreiga

here is my page which reads product files from a directory and shows them on dynamic created multiple pages.
Some info: $xml is my class which reads xml product files, included 'general*.php" files are the header, footer and some functions (classes declarations etc.).
If you do not understand some of my code (because of uncommented parts or of the poor optimization please tell me).

<?php
require_once('cookie.php');
?>

<html>

<head>
<?php
require_once('general1.php');
?>
<title>
Welcome to ProArtist - Where Art Meets You
</title>
<?php
require_once('general2.php');
?>
</head>

<body>
<?php
require_once('general3.php');

echo "<tr><td colspan=\"6\" align=\"left\" valign=\"top\">";

$handle = opendir(PRODUCTS_DIR);
while(false != ($file = readdir($handle)))
{ 
	if(strstr($file, '.gz'))
	{
		$filename[] = PRODUCTS_DIR.$file;
	}
}
closedir($handle);

if(!isset($_SESSION["product_list"]))
{
	while($file = array_shift($filename))
	{
		//opens and reads data file in $src
		$fp = gzopen($file, 'rb');
		if(!$fp)
		{
			 ShowMessageBox('FILE='.__FILE__.'\nLine='.__LINE__.'\nUnable to open '.$file);
			 exit(0);
		}
		$src = gzread($fp, MAX_FILESIZE);
		if(!$src)
		{
			 ShowMessageBox('FILE='.__FILE__.'\nLine='.__LINE__.'\nUnable to read from '.$file);
			 exit(0);
		}
		gzclose($fp);

		//creates and parses an XML
		$xml = new XML;
		$result = $xml->Create($src, NULL);
		if($result != 'ok')
		{
			ShowMessageBox('FILE='.__FILE__.'\nLine='.__LINE__.'\nxml.Create() error -> '.$result);
			exit(0);
		}

		//reads the artist
		$result = $xml->SetCurrentNode($xml->root, 'artist', 0);
		if($result != 'ok')
		{
			ShowMessageBox('FILE='.__FILE__.'\nLine='.__LINE__.'\nxml.SetCurrentNode() error -> '.$result);
			exit(0);
		}
		$artist = $xml->GetNodeContent();

		//reads the category
		$result = $xml->SetCurrentNode($xml->root, 'category', 0);
		if($result != 'ok')
		{
			ShowMessageBox('FILE='.__FILE__.'\nLine='.__LINE__.'\nxml.SetCurrentNode() error -> '.$result);
			exit(0);
		}
		$category = $xml->GetNodeContent();

		//checks for the category and artist and skips the product if necessary
		if(($artist != $_SESSION["current_artist"]) && ($category != 'New Testament'))
		{
			unset($xml);
			continue;
		}

		//reads the title
		$result = $xml->SetCurrentNode($xml->root, 'title', 0);
		if($result != 'ok')
		{
			ShowMessageBox('FILE='.__FILE__.'\nLine='.__LINE__.'\nxml.SetCurrentNode() error -> '.$result);
			exit(0);
		}
		$title = $xml->GetNodeContent();

		//reads the id
		$result = $xml->SetCurrentNode($xml->root, 'id', 0);
		if($result != 'ok')
		{
			ShowMessageBox('FILE='.__FILE__.'\nLine='.__LINE__.'\nxml.SetCurrentNode() error -> '.$result);
			exit(0);
		}
		$id = $xml->GetNodeContent();

		//reads the imagename
		$result = $xml->SetCurrentNode($xml->root, 'image', 0);
		if($result != 'ok')
		{
			ShowMessageBox('FILE='.__FILE__.'\nLine='.__LINE__.'\nxml.SetCurrentNode() error -> '.$result);
			exit(0);
		}
		$imagename = $xml->GetNodeContent();
		$imagename = 'images/products/'.basename($imagename, '.jpg').'low.jpg';

		//deletes $xml object
		unset($xml);

		$_SESSION["product_list"][] = array("title" => $title, "id" => $id, "imagename" => $imagename);
	}
	sort($_SESSION["product_list"]);
	$current_type = '';
	for($i=0; $i<sizeof($_SESSION["product_list"]); $i++)
	{
		$value = $_SESSION["product_list"][$i];
		$type = explode(" - Version No.", $value["title"]);
		$type = $type[0];
		if($current_type != $type)
		{
			$_SESSION["index_themes"][] = $i;
			$current_type = $type;
		}
	}
	$_SESSION["index_themes"][] = $i;
}

if(!isset($_SESSION["high_theme"]))
{
	$_SESSION["low_theme"] = 0;
	$_SESSION["high_theme"] = MAX_THEMES_PER_PAGE-1;
}
if(isset($_POST["previous"]))
{
	$_SESSION["low_theme"] -= MAX_THEMES_PER_PAGE;
	$_SESSION["high_theme"] -= MAX_THEMES_PER_PAGE;
	unset($_POST["previous"]);
}
else if(isset($_POST["next"]))
{
	$_SESSION["low_theme"] += MAX_THEMES_PER_PAGE;
	$_SESSION["high_theme"] += MAX_THEMES_PER_PAGE;
	unset($_POST["next"]);
}
/*
if(isset($_GET["btn_page"]))
{
	if($_GET["btn_page"] == "next")
	{
		$_SESSION["low_theme"] += MAX_THEMES_PER_PAGE;
		$_SESSION["high_theme"] += MAX_THEMES_PER_PAGE;
	}
	else if($_GET["btn_page"] == "previous")
	{
		$_SESSION["low_theme"] -= MAX_THEMES_PER_PAGE;
		$_SESSION["high_theme"] -= MAX_THEMES_PER_PAGE;
	}
	unset($_GET["btn_page"]);
}
*/
echo $_SESSION["low_theme"]." , ".$_SESSION["high_theme"]."<br>";
echo "<h3>Click on a image for a full description</h3>";
echo "<table border=\"0\">";
for($i=0; $i<sizeof($_SESSION["index_themes"])-1; $i++)
{
	if($i < $_SESSION["low_theme"])
	{
		continue;
	}
	if($i > $_SESSION["high_theme"])
	{
		break;
	}
	$value = $_SESSION["product_list"][$_SESSION["index_themes"][$i]];
	$title = explode(" - Version No.", $value["title"]);
	$title = $title[0];
	$nr_cells = 0;
	echo "<tr><td align=\"center\" colspan=\"6\"><h2>".($i+1).". ".$title."</h2></td></tr>";
	echo "<tr align=\"center\" valign=\"middle\">";
	for($j=0; $j<($_SESSION["index_themes"][$i+1]-$_SESSION["index_themes"][$i]); $j++)
	{
		$nr_cells++;
		if(($nr_cells % (MAX_VERSIONS_PER_ROW+1)) == 0)
		{
			echo "</tr>";
			echo "<tr align=\"center\" valign=\"middle\">";
		}
		$value = $_SESSION["product_list"][$_SESSION["index_themes"][$i]+$j];
		echo "<td width=\"190\" height=\"230\">";
		echo "<a href=\"product.php?id=".$value["id"]."\">";
		echo "<img alt=\"".$value["title"]."\" border=\"0\" name=\"button".$value["id"]."\" 
					onmouseover=\"window.status = '".$value["title"]."'; document.button".$value["id"].".border='2'; return true;\" 
					onmouseout=\"window.status = ''; document.button".$value["id"].".border='0'; return true;\" 
					src=\"".$value["imagename"]."\"/></a>";
		echo "</td>";
	}
	echo "</tr>";
	echo "<tr><td colspan=\"10\"><hr size=\"5\" noshade></td></tr>";
}
echo "</table>";

/
echo "<tr>";
echo "<td align=\"left\" colspan=\"3\">";
if($SESSION["low_theme"] != 0)
echo "<a href=\"".$SERVER['PHP_SELF']."?btn_page=previous\">Previous Page</a>";
echo "</td>";
echo "<td align=\"right\" colspan=\"3\">";
if($SESSION["high_theme"] != (sizeof($SESSION["index_themes"])-1))
echo "<a href=\"".$_SERVER['PHP_SELF']."?btn_page=next\">Next Page</a>";
echo "</td>";
echo "</tr>";
/

echo "<tr>";
echo "<form name=\"pageform\" action=\"".$_SERVER['PHP_SELF']."\" method=\"POST\">";
echo "<td align=\"left\" colspan=\"3\">";
if($_SESSION["low_theme"] != 0)
	echo "<input type=\"submit\" name=\"previous\" value=\"Previous Page\">";
echo "</td>";
echo "<td align=\"right\" colspan=\"3\">";
if($_SESSION["high_theme"] != (sizeof($_SESSION["index_themes"])-1))
	echo "<input type=\"submit\" name=\"next\" value=\"Next Page\">";
echo "</td>";
echo "</form>";
echo "</tr>";

echo "</td></tr>";

require_once('general4.php');
?>

</body>

</html>