Yet Another Tetris

I just uploaded my version of the Tetris.
Go to Games page to play it !-)

In order to get familiar with the JavaScript language I have decided to implement a couple of games. Tetris was the number one on my list. Minesweeper will be the next one.

I've tested my code on Windows XP SP3 and Windows 7 Professional. The following browsers run the game fine:

• Firefox v4.0 Beta 6
• Google Chrome 7.0
• Opera 10.63
• Safari 5.0.2

JavaScript and Canvas, woo hoo!

HTML5 standard introduces the Canvas element. We can now draw on a web page with plain JavaScript code. Isn't this exciting?

I have a few old games which I wrote in Turbo Pascal (and Delphi) and I intend to convert them into JavaScript code and post them in my blog, so anyone can play them. Woo hoo!

If your browser does support the canvas tag/element you'll be able to view a white square with a black border below. If so, try rolling the mouse over the square. If no, consider upgrading your browser ;-)


no canvas support



That's my Black Triangle.

timestampToString, Google's obfuscated code sample

When we search on Google, we sometimes see a time-stamp on the results.

Example:

What code does that job?

Well, here it is:

function sa(a,c){var b=c-a;if(b<86400)if(b<45)return"seconds ago";else if(b<105)return"1 minute ago";else if(b<3345){b=Math.floor(b/60)+(b%60>=45?1:0);return"1 minutes ago".replace("1",b+"")}else if(b<6600)return"1 hour ago";else{b=Math.floor(b/3600)+(b%3600>=3E3?1:0);return"1 hours ago".replace("1",b+"")}return g}

1-liner (kinda :-) obfuscated JavaScript code. Yeah, Google obfuscates the source code which is revealed to the public. Most function names, along with constant values, and white-space, are removed or replaced with shorter, meaningless names.

To get the code, go to Google home page, and use whatever option your favorite browser provides for viewing the source code.  In there, search for a URL string like this one:

/extern_js/f/CgJlbhICZ3IrMA ... BROAIsKzBaOAAsgAIV/0JBXC50vuSQ.js

If you attach it at the end of the Google URL, you'll get the whole source code.

ie, http://google.com/extern_js/...

Now, with a proper indentation, sa function becomes readable:

function sa(a, c) {
  var b = c - a;
  if (b < 86400)
      if (b < 45)
         return "seconds ago";
      else if (b < 105)
         return "1 minute ago";
      else if (b < 3345) {
         b = Math.floor(b / 60) + (b % 60 >= 45 ? 1:0); 
         return "1 minutes ago".replace("1", b + "")
      }
      else if (b < 6600)
         return "1 hour ago";
      else {
         b = Math.floor(b/3600) + (b%3600 >= 3E3 ? 1:0);
         return "1 hours ago".replace("1", b + "")
      }
  return g
}

If we know JavaScript, or another programming language with similar syntax, it's pretty easy to see that the time-stamp is displayed only on pages that were updated, in Google Index, in less than a day (86400 = 24 x 60 x 60 seconds).

Here is the final (unobfuscated) version, written in Python this time:

import math
def timestampToString(currentTime, modifiedTime):
   delta = currentTime - modifiedTime
   if delta < 86400:
      if delta < 45:
         return "seconds ago"
      elif delta < 105:
         return "1 minute ago"
      elif delta < 3345:
         delta = math.floor(delta / 60) + (1 if delta % 60 >= 45 else 0)
         return "%i minutes ago" % delta
      elif delta < 6600:
         return "1 hour ago";
      else:
         delta = math.floor(delta / 3600) + (1 if delta % 3600 >= 3000 else 0)
         return "%i hours ago‚" % delta
   return False

Did you notice that the value 3000 was, in the equivalent scientific notation, 3E3? Cool ;-)