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Using the strip_tags() function on any user generated input should be common practice in order to stop users putting in odd bits of HTML and messing up your nicely coded HTML. You might want to allow anchor tags to be used, which is fine, but some users might use this to include onmouseover and other events in order to run JavaScript annoyances on the page.

So after stripping all tags from your text you can then run the following function to turn any links into anchor elements. This will work with any plain text that you want to use it on.

The following section of JavaScript will detect if anyone is viewing your page in a frame. If they are then the code will redirect them to your site. It essentially stops people using frames to poach your content and stops online proxy software from viewing your site.

if (top.location != location) {
 top.location.href = document.location.href;
}

All you have to do is include this code either in your script tag or your JavaScript includes. Quite a neat little trick really.

To create a simple PHP visit counter you will need to create a plain blank text file called counter.txt.

Put the following two functions into a file and include it at the top of any page that you want to have counted.

function loadCounter()
{
 if ( file_exists('counter.txt') ) {
  $n = file_get_contents('counter.txt');
  return intval($n);
 }
 return 0;
}

The updateCounter() function.

function updateCounter($i=1)
{
 
 $n = loadCounter();
 $n += $i;
 
 $fp = fopen('counter.txt',"w+");
 fwrite($fp, $n);
 fclose($fp);
 
 return $n;
}

The two functions work together to create the counter. If you only want to display the number of times that a page has been visited then just call the loadCounter() function.

The following function takes a path as an argument and produces an array of files ordered by their timestamp. The array values are the filename and the array keys are the timestamps. In order to prevent two files that have the same timestamp overwriting each other when the array keys are created with a random number. If two files where created at the same time the least that will happen is that they will swap places every time the array is created as the random number will be different.

function listDirectoryByDate($path) {
 $dir = opendir($path);
 $list = array();
 while ($file = readdir($dir)) {
  if ($file != '.' && $file != '..' && !is_dir($file)) {
   $ctime = filectime($path.$file) . rand(1000,9999);
   $list[$ctime] = $file;
  }
 }
 closedir($dir);
 krsort($list);
 return $list;
}

To use the function to print out all of the files in the current directory use the following code.

To get the class of an element with JavaScript you use the className property of the element object. Take the following section of HTML code.

<div id="adiv" class="theClass">some text</div>

Use the following bit of code to print off the class name of the div element in a message box.

alert(document.getElementById('adiv').className);

To set the class name to something else you can use the same property, but in this case just pass it a value. The following example changes the class name of the div element to 'newClass'.

Printing off a random quote on a page is useful (or at least interesting), but it is nice to rotate them slower than every page view.

A better solution is to use a time based value to work out which quote to display. In this way the quote is changed every hour/day/week or whatever time period you have selected.

Create a file called quote.txt in the same directory as the script and put a single quote on each line.

quote 1
quote 2
quote 3

The following function will take a time part as a single parameter and return a quote.

To get a webpage to refresh every few seconds you can use a meta tag with the attribute http-equiv and a value of refresh. The number of seconds to delay can be put into the content attribute. This meta tag (as will all meta tags) goes into the head section of the document.

Here is an example that refreshes the page every 2 seconds.

<meta http-equiv="refresh" content="2" />

It is also possible to make the browser refresh to another page by including the string:

url=url or filename

Within the content attribute. Here is an example that redirects the page to google.com after a 5 second delay.

<meta http-equiv="refresh" content="5;url=http://www.google.com" />

Here is a short bit of code to generate a random hexadecimal colour using PHP. Essentially you just create a random number between 0 (000000) and 10,000,000 (ffffff) and turn this into a hexadecimal number using the PHP function dechex.

$colour = rand(0, 10000000);
$colour = dechex($colour);

This can also be accomplished on a single line.

$colour = dechex(rand(0, 10000000));

It is sometimes necessary to block people from using your site, dependent on their IP address. A users IP address can be detected by PHP using the $_SERVER superglobal and the parameter REMOTE_ADDR.

The code includes two ways to load the list of IP addresses. The first is by hard coding it into an array, and the second is by the use of a plain text file called "blocked_ips.txt". The format of this file is simply a list of IP addresses, with one address on each line. Through the use of the file() function this file is loaded as an array into of addresses.

To stop access to a directory (and anything in that directory) all you need is a simple RewriteRule.

RewriteEngine on
RewriteBase /
RewriteRule ^exampledirectory/(.*)$ / [R=301,L]

In this example, if this .htaccess file resides in the root directory of the site and you try to access anything within /exampledirectory you will be redirected back to the root folder. To redirect to another folder (like anotherdirectory) on your web server use the following rule.

RewriteEngine on
RewriteBase /
RewriteRule ^exampledirectory/(.*)$ /anotherdirectory [R=301,L]