Hello everyone!
I have a tumblr and a cool thing about it is that it's possbile to add a page to it. For example, if the url of tumblr is "http://processing.tumblr.com", additional page could be "http://processing.tubmlr.com/page1" and it can have a completely different source code. I wanted to have such a page that will consist completely of a processing sketch and the source code looks like this:

1. <script src="https://github.com/downloads/processing-js/processing-js/
2. processing-1.3.6.js"></script>
3. <script type="text/processing" data-processing-target="mycanvas">
4. float rad = 50;
5. float alpha = 0;
6. float odmak = rad/2;
7. int rate = 60;
8. float k=20;
9. float xx=0;
10. float rr = 127, gg = 195, bb = 81;
11. float x, y;
12. float vrim;
13. float taj = 0;
14. void setup() {
15.   size(screen.width - 20, screen.height - 192);
16.   background(0);
17.   stroke(255);
18.   noFill();
19.   smooth();
20.   frameRate(rate);
21. }
22. void draw() {
23.   fill(0, 0);
24.   rect(0, 0, width, height);
25.   fill(rr, gg, bb);
26.   alpha += k;
27.   odmak += rad/(360/k);
28.   k = 500/odmak;
29.   rad += xx;
30.   xx += 0;
31.   x = odmak*cos(radians(alpha));
32.   y = -odmak*sin(radians(alpha));
33.   vrim = millis() - taj;
34.   rr = 127 - 127*sin(0.000026*vrim);
35.   gg = 150 - 55*sin(0.000022*vrim - 1);
36.   bb = 127 + 50*sin(0.000046*vrim - 2);
37.   translate(width/2 + x, height/2 + y);
38.   ellipse(0, 0, rad, rad);
39. }
40. void mouseClicked() {
41.   background(0);
42.   rad = 50;
43.   alpha = 0;
44.   odmak = rad/2;
45.   rate = 60;
46.   k = 20;
47.   xx = 0;
48.   rr = 127;
49.   gg = 195;
50.   bb = 81;
51.   taj = millis();
52. }
53. </script>
54. <canvas id="mycanvas"></canvas>

It's a simple program that draws a spiral, I know it's quite ugly but that's not important. The thing that bugs me is the line size(screen.width - 20, screen.height - 192);. It sets the sketch size to a screen size substracted by 20 and 192 pixels and I chose those numbers because firefox adds a little border horizontaly and I had to substract so much verticaly because there is a browser menu on the top and windows toolbar on the bottom.
What I want is that the sketch size is set exactly to the browser window size automatically so that my sketch can use the "full potential" of a browser.

I hope I was clear about the thing I want and if the answer consists of javascript coding pleeease be specific about it because I really don't know javascript that much. I found some solutions that include javascript but I'm really nowhere near understanding it..

Thanks in advance, here's the result (for now) : http://patakk.tumblr.com/spir