Have you ever tried accessing a website and it didn’t respond? Of course you have. We all have! Mr Uptime is an extension to your Firefox browser that will keep trying to reach that website in the background while you continue surfing on other websites. When the website is accessible again, Mr Uptime will let you know. You can also use Mr Uptime when a website responds but doesn’t load correctly.

Get notified when an unavailable website starts to work again.

I'm building an online cash register and decided to use XAJAX as my PHP/Ajax toolkit. It was very easy to learn and begin using. In fact, I am amazed at how easy XAJAX is to use. The problem, it is still in the infancy stage and today I found that not all responses work as expected.

I needed to replace an element like this

The expected result would be the HTML tag and text,

would be replaced with

I just couldn't get it to work. It appears that the problem is with Firefox. I didn't try IE but from what others have said, addReplace works in IE.

I finally had to come up with a workaround because I needed this to work in both IE and FF.

Simple, eh?

I have noticed an unusual amount of emails being received with no body text, just a .pdf file attached. I don't open any attachment unless I am expecting it, so the email goes immediately to the trash. After doing some research, I found that apparently attaching a .pdf file is the spammers new method of choice.

Seems like a pretty benign method of spreading spam.

This is a fascinating look at how one person tracked down a hacker who broke into a buddy's Linux server.

I found a pretty cool list of Thunderbird Add-ons with some real gems like the add notes to email extension and the folder shortcuts.

I'm constantly reminded how much I love Mozilla applications!

CSS Redundancy Checker

A simple script that, given a CSS stylesheet and either a .txt file listing URLs of HTML files, or a directory of HTML files, will iterate over them all and list the CSS statements in the stylesheet which are never called in the HTML.

Basically, it helps you keep your CSS files relevant and compact. And it's reasonably accurate.

Unfortunately for me it requires Rubygems and Hpricot, plus a reasonably up-to-date version of Ruby.

Apple has a new website, looks a lot like iTunes on the web. Pretty cool. I also noticed that the Safari browser, formally only available to MAC users, now comes in a Microsoft version.

1. Blazing Performance - 2x Faster - Safari is the fastest web browser on any platform.
2. Elegant User Interface - Safari’s clean look lets you focus on the web — not your browser.
3. Easy Bookmarks - Organize your bookmarks just like you organize music in iTunes.
4. Pop-up Blocking - Say goodbye to annoying pop-up ads and pop-under windows.
5. Inline Find - Search any text on any website with the integrated Find banner.
6. Tabbed Browsing - Open and switch between multiple web pages in a single window.
7. Snapback - Instantly snap back to search results or the top level of a website.
8. Forms AutoFill - Let Safari complete online forms for you, automatically and securely.
9. Built-in RSS - RSS tells you when new content is added to your favorite sites.
10. Resizable Text Fields - Resize text fields on any website: Just grab the corner and drag.
11. Private Browsing - Keep your online activities private with a single click.
12. Security - Apple engineers designed Safari to be secure from day one.

All major browsers change the color of links users have visited. With some JavaScript, a web site can view the colors of the links in a users browser history and determine if they have visited a site. A web site can't pull a list of sites the user has visited from their browser, but they can test a predefined list of URL's to see if they have visited any of them.

Spyjax makes it super easy for web sites to spy on their visitors. With Ajax, thousands of links can be tested against a visitors browser history to determine which web sites have been visited.

Luckily, if you're a Firefox user, there is SafeHistory. A Firefox add-on that restricts the marking of visited links on the basis of the originating document, defending against web privacy attacks that remote sites can use to determine your browser history at other sites.

Finally I can log into my Google Calendar and view and add events.

Just visit calendar.google.com from your phone, and you'll see your agenda of upcoming events, complete with details like date, time, location, description, and guest list.

If you find that your phone number is in Google Search you can have it removed here.

Using the uptime command on one of my Red Hat Linux servers

Let's see you keep your Windows server online for 258 days without a restart.

I recently stumbled upon a free CSS editor available for Windows, Mac and Linux.

To help you work with CSS, we've created a free tool called Simple CSS, which runs on Macs, Windows and Linux. Simple CSS allows you to easily create Cascading Style Sheets from scratch, and/or modify existing ones, using a familiar point-and-click interface.

Simple CSS

Whitelist For Exim Sender Verify Callout

Recently a user called and said that he was not receiving emails from a particular person. The email was being sent, but not received by the user. After verifying that the email was not getting caught up in a spam filter, I looked through the Exim logs located at /var/log/exim_mainlog. I found the email was being rejected with the error

could not complete sender verify callout

Exim by default, will check the senders email address and send a callback to the sending server to check and see if the users email address actually exists. In this case the senders email server was not verifying the email address actually exists and so the email was being rejected.

I didn't want to turn off callouts to verify the existence of email senders so I did some digging and found that Exim allows the callout feature to check with a whitelist to see if a callout instruction should be ignored. The instructions were locked within the cPanel forums which require registration and so my Google check didn't find these instructions.

I'm posting them here in hopes that others can find them easily. The original forum post is located here.

Create a file that will be the actual whitelist. In this example it is /etc/whitelist_senders - the addresses need to be listed one entry per line, either the email address or use the wildcard to do an entire domain. To create the file:

In WHM, in the top most edit box add (if there is anything else in the text box add this bellow it):

Still in WHM. scroll down to where there are three text boxes together. This is the begin ACL section. In the middle box scroll down until you find:

and change it to:

Still in the middle box scroll down to the end and change:

to this:

Save and exit. Now try to send and receive email to make sure everything is still working. If all is ok add the address in question to the whitelist and see if it works.

Then put the sender addresses in the file /etc/whitelist_senders, one per line, e.g.

I have been receiving some strange emails lately. The latest one goes like so

Do not reply to this message

Dear Customer,

Our robot has fixed an abnormal activity from your IP address on sending e-mails. Probably it is connected with the last epidemic of a worm which does not have patches at the moment. We recommend you to install a firewall module and it will stop e-mail sending. Otherwise your account will be blocked until you do not eliminate malfunction.

Customer support center robot

A zipped file is attached. I didn't unzip the file but this has all the characteristics of an email virus. As always, never open a file attachment from someone you don't know.

Condiment Conundrum