This is the code shared by Jose on codewall. When you type data:text/html,   into the address bar of the browser and press enter, the browser will turn into a notepad which you can edit.Why it works?This uses Data URI’s format and it tells the browser to render HTML. But contenteditable is a property of HTML5, so this can only work in the web browser which supports this property.Here are some interesting contents.Some people make some changes to the code encouraged by the idea of Jose.jakeonrails wrote one line of code which supports Ruby code highlighting. Here is the code:dat...