Suppose you have a message and it says:
What The Slug is trying to say is:
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.
which translate text into ASCII and ASCII into text. For example, with unescape() you can convert the ASCII representations to their non alphanumeric equivalents, all that's left is to replace the plus signs ("+") with spaces (" "). Here are two simple URL Decoding scripts:
Type a message into the text box below and click Encode. The script URL Encodes your message just like your web server would and the results appear in the lower text box. Now just click Decode and a script similar to the one above Decode your message back into it's original form.