Today I will be posting a short article because I didn’t know I would be so tied up with the Live Support that I launched yesterday. Some of the cases were really tough but still managed to helped a few users and I am feeling really good about it. Anyway, have you ever noticed that there are times you’ll see weird characters such as %20, %3A and etc in webpages especially in URLs? These characters are called percent encoding and the 2 characters after the percentage sign actually represents a “reserved” character. Let’s do a simple test here if you don’t know what I am talking about. Open up Internet Explorer, type http://www.google.com/” in the URL and hit enter. Make sure you add a double quote after the slash. You will instantly see that the double quotes is being converted into %22.

Two days ago I received a copyright infringement notice and was asked to reply with the following subject RE%3A%20Copyright%20Infringement%20Notice%20ID%3A%20XXX%2DXXXXXXX or else my email would be treated as spam. I have done research on this before but I did not save the website that provided simply decoding to the percent encoding characters. When I really needed it again, I had to spend time looking up on the same thing that I’ve researched before. I am posting this out so I know where I can look it up in future and also hope that you guys can learn something new too.
There are 20 reserved characters including space ! * ‘ ( ) ; : @ & = + $ , / ? % # [ ] that has to be encoded only under certain circumstances. You can refer to the table below to manually convert the percent encoding to a character.

Surely I am not going to memorize all those hex codes, so here is a website that has an online tool for automatic URL Encoding and Decoding.
Simply enter the percent encoded URL to the form and hit the Decode button. Voila, the decoded text shows immediately.

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I observed this when saving PDFs from websites. Quite irritating actually. Now that I know the reason, feel better :-)
Thanks, it´s a nice timesaver tool to have, anyway as I prefer an offline one I did some search and found bosseye.com/escaped_encoding/index.htm :)
Are you sure ‘@’ is still a reserved character ? I’m experimenting capturing raw URL data from a POST form and noticing that ‘@’ is no longer being encoded as ‘%40′ as I expected.
Or you could just type into the top of your browser javascript:alert(\”RE%3A%20Copyright%20Infringement%20Notice%20ID%3A%20XXX%2DXXXXXXX\”) and a message box pops up.
thanks ray for sharing ill need this for later
Thanks Ray!
woooow … thanks man …
Hello,
For Firefox users, the “Hackbar” extension can URLencode / decode (and much more) any URL for you.
Gr8 info that ones doesn’t stop to look up.
The last box in your table should include %20 to be complete…
Thanks again.
I was intrigues dome time ago with this issues, hopping that was not spams.
Some characters (like non-printing characters) are invalid in URLs. Other characters (like &) can’t be placed in a URL querystring without changing the meaning of that querystring.
Problems with these characters can all be fixed by ‘escaping’ them. This process involves scanning the text for those characters, and replacing them with a special character-code that browsers can interpret as the correct symbol, without actually using that symbol in your URL.
For example, the escaped character code for ‘=’ is ‘%3d’.
The string above is called URL Encoding, a scheme in which text data transmitted to web servers is encoded by replacing spaces (” “) with plus signs (“+”) and non alpha numeric characters are replaced by their ASCII equivalents.
It’s almost trivially simple to URL Encode text because JavaScript has two functions:
1)escape() and
2)unescape()
permadi.com/tutorial/urlEncoding/
Well its helpful perhaps for webmasters
good info buudy thanx
thanks looks intresting..