Category Archive for “Function”

Here is a list of all articles categorized as “Function”. If you enjoy the high-quality content that I provide here at Perishable Press, you may want to subscribe to our main content feed to stay current.

htaccess Redirect to Maintenance Page

Redirecting visitors to a maintenance page or other temporary page is an essential tool to have in your tool belt. Using HTAccess, redirecting visitors to a temporary maintenance page is simple and effective. All you need to redirect your visitors is the following code placed in your site’s root HTAccess: # MAINTENANCE-PAGE REDIRECT RewriteEngine on RewriteCond %{REMOTE_ADDR} !^123\.456\.789\.000 RewriteCond %{REQUEST_URI} !/maintenance.html$ [NC] RewriteRule .* /maintenance.html [R=302,L] That is the official copy-&-paste goodness right there. Just grab, gulp and go. Of course, there are a few more details for those who may be unfamiliar with the process. Let’s look at all the gory details.. Redirecting Traffic with HTAccess To redirect your visitors to a maintenance page, ...

Stop 404 Requests for Mobile Versions of Your Site

If you’ve been keeping an eye on your 404 errors recently, you will have noticed an increase in requests for nonexistent mobile files and directories, especially over the past year or so. The scripts and bots requesting these files from your server seem to be looking for a mobile version of your site. Unfortunately, they are wasting bandwidth and resources in the process. It has become common to see the following 404 errors constantly repeated in your log files: http://domain.tld/apple-touch-icon.png http://domain.tld/iphone http://domain.tld/mobile http://domain.tld/mobi http://domain.tld/m So some bot comes along, assumes that your site includes a mobile version, and then tries its hand at guessing the ...

Is it Secret? Is it Safe?

Whenever I find myself working with PHP or messing around with server settings, I nearly always create a phpinfo.php file and place it in the root directory of whatever domain I happen to be working on. These types of informational files employ PHP’s handy phpinfo() function to display a concise summary of all of your server’s variables, which may then be referenced for debugging purposes, bragging rights, and so on. While this sort of thing is normally okay, I frequently forget to remove the file and just leave it sitting there for ...

3 Ways to Track Web Pages with Google Analytics

Many bloggers, designers, and developers take advantage of Google’s free Analytics service to track and monitor their site’s statistics. Along with a Google account, all that’s needed to use Google Analytics is the addition of a small slice of JavaScript into your web pages. For a long time, there was only one way of doing this, and then in 2007 Google improved their GATC code and established a new way for including it in your web pages. Many people switched over to the newer optimized method, but may not realize that there are now three different ...

Better Image Preloading with CSS3

I recently added to my growing library of image-preloading methods with a few new-&-improved techniques. After posting that recent preloading article, an even better way of preloading images using pure CSS3 hit me: .preload-images { background: url(image-01.png) no-repeat -9999px -9999px; background: url(image-01.png) no-repeat -9999px -9999px, url(image-02.png) no-repeat -9999px -9999px, url(image-03.png) no-repeat -9999px -9999px, url(image-04.png) no-repeat -9999px -9999px, url(image-05.png) no-repeat -9999px -9999px; } Using CSS3’s new support for multiple background images, we can use a single, existing element to preload all of the ...

3 Ways to Preload Images with CSS, JavaScript, or Ajax

Preloading images is a great way to improve the user experience. When images are preloaded in the browser, the visitor can surf around your site and enjoy extremely faster loading times. This is especially beneficial for photo galleries and other image-heavy sites where you want to deliver the goods as quickly and seamlessly as possible. Preloading images definitely helps users without broadband enjoy a better experience when viewing your content. In this article, we’ll explore three different preloading techniques to enhance the performance and usability of your site. Method 1: Preloading with CSS and JavaScript There are many ways to preload images, including methods that rely on CSS, JavaScript, and ...

Really Simple Browser Detection with jQuery

For my Serious redesign, I push the envelope in terms of CSS’ advanced selector functionality. Stuff like: p:first-child p:first-child:first-letter p:first-child:after p:first-child:first-line Plus lots of other stylistic tricks that require CSS3 support in order to display as intended. Fortunately, most of the browsers to which I am catering with this new design have no problems with most of the advanced stuff. Of course, Internet Explorer chokes on just about everything, but fortunately IE’s proprietary conditional comments make it easy to fix things up with some “special” styles:...

Pimp Your 404: Presentation and Functionality

I have been wanting to write about 404 error pages for quite awhile now. They have always been very important to me, with customized error pages playing a integral part of every well-rounded web-design strategy. Rather than try to re-invent the wheel with this, I think I will just go through and discuss some thoughts about 404 error pages, share some useful code snippets, and highlight some suggested resources along the way. In a sense, this post is nothing more than a giant “brain-dump” of all things 404 for future reference. Hopefully you will find it useful in pimping your own 404. When requested page is not found by server, error message ...

HTAccess Privacy for Specific IPs

Running a private site is all about preventing unwanted visitors. Here is a quick and easy way to allow access to multiple IP addresses while redirecting everyone else to a custom message page. To do this, all you need is an HTAccess file and a list of IPs for which you would like to allow access. Edit the following code according to the proceeding instructions and place into the root HTAccess file of your domain: # ALLOW ONLY MULTIPLE IPs Order Deny,Allow Deny from all Allow from 123.456.789 Allow from 456.789.123 Allow from 789.123.456 ErrorDocument ...

Disable Trace and Track for Better Security

The shared server on which I host Perishable Press was recently scanned by security software that revealed a significant security risk. Namely, the HTTP request methods TRACE and TRACK were found to be enabled on my webserver. The TRACE and TRACK protocols are HTTP methods used in the debugging of webserver connections. Although these methods are useful for legitimate purposes, they may compromise the security of your server by enabling cross-site scripting attacks (XST). By exploiting certain browser vulnerabilities, an attacker may manipulate the TRACE and TRACK methods to intercept your visitors’ sensitive data. The solution, of ...

HTAccess Password-Protection Tricks

Recently a reader asked about how to password-protect a directory for every specified IP while allowing open access to everyone else. In my article, Stupid htaccess Tricks, I show how to password-protect a directory for every IP except the one specified, but not for the reverse case. In this article, I will demonstrate this technique along with a wide variety of other useful password-protection tricks, including a few from my Stupid htaccess Tricks article. Before getting into the juicy stuff, we’ll review a few basics of HTAccess password protection. HTAccess password protection works in cascading fashion Before we begin, there are few things ...

Block Multiple IP Addresses with PHP

Let’s face it. There’s just as much scum on the Internet as there is out there in the “real world.” Maybe even more, who knows. From scammers and spammers to scrapers and crackers, the Web is just crawling with all sorts of pathetic scumbags. As predictably random as much of the malicious activity happens to be, it is virtually guaranteed that you will be hounded by at least a few persistent IP addresses ...

9 Ways to Set Dynamic Body IDs via PHP and WordPress

When designing sites, it is often useful to identify different pages by adding an ID attribute to the element. Commonly, the name of the page is used as the attribute value, for example: In this case, “about” would be the body ID for the “About” page, which would be named something like “about.php”. Likewise, other pages would have unique IDs as well, for example: ..again, with each ID associated with the name of the page. This identification strategy is useful for a variety of reasons, including the following: Page-specific control over CSS via descendant selectors Page-specific DOM manipulation via ...

HTAccess Spring Cleaning 2009

Just like last year, this Spring I have been taking some time to do some general maintenance here at Perishable Press. This includes everything from fixing broken links and resolving errors to optimizing scripts and eliminating unnecessary plugins. I’ll admit, this type of work is often quite dull, however I always enjoy the process of cleaning up my HTAccess files. In this post, I share some of the changes made to my HTAccess files and explain the reasoning behind each ...

Controlling Proxy Access with HTAccess

In my recent article on blocking proxy servers, I explain how to use HTAccess to deny site access to a wide range of proxy servers. The method works great, but some readers want to know how to allow access for specific proxy servers while denying access to as many other proxies as possible. Fortunately, the solution is as simple as adding a few lines to my original proxy-blocking method. Specifically, we may allow any requests coming from our whitelist of proxy servers by testing Apache’s HTTP_REFERER variable, like so: RewriteCond %{HTTP_REFERER} !(.*)allowed-proxy-01.domain.tld(.*) RewriteCond %{HTTP_REFERER} !(.*)allowed-proxy-02.domain.tld(.*) RewriteCond ...

Remove the WWW Prefix for all URLs via PHP

Canonical URLs are important for maintaining consistent linkage, reducing duplicate content issues, and increasing the overall integrity of your site. In addition to cleaning up trailing slashes and removing extraneous index.php and index.html strings, removing the www subdirectory prefix is an excellent way to shorten links and deliver consistent, canonical URLs. Of course, an optimal way of removing (or adding) the www prefix is accomplished via HTAccess canonicalization: # universal www canonicalization via htaccess # remove www prefix for all urls - replace all domain and tld with yours # http://perishablepress.com/press/2008/04/30/universal-www-canonicalization-via-htaccess/ RewriteEngine On RewriteBase / RewriteCond %{HTTP_HOST} !^domain\.tld$ ...

Eight Ways to Blacklist with Apache’s mod_rewrite

With the imminent release of the next series of (4G) blacklist articles here at Perishable Press, now is the perfect time to examine eight of the most commonly employed blacklisting methods achieved with Apache’s incredible rewrite module, mod_rewrite. In addition to facilitating site security, the techniques presented in this article will improve your understanding of the different rewrite methods available with mod_rewrite. Blacklist via Request Method This first blacklisting method evaluates the client’s request method. Every time a client attempts to connect to your server, it sends a message indicating the type of connection it wishes to make. ...