Great work, as always. And only 20 lines? amazing.

Only criticism so far is that mario moves a little too fast. Other than that, plays fine.

Browser?
He does seem to run a bit too fast in FF3 and the ground seems more slippery. I'll try to tweak it.

James Urquhart: Our definition of "effective" line of code is rather lax, but you'd be surprised to see what's possible within these loose constraints. Just look at the previous editions of the 20 lines JavaScript contests.

Jacob Seidelin: Well done Sir. Too bad the setInterval(foo,40) and the DIV "soup" manipulation are killing most browsers.

In the context of a 20 liner, it would have been perfectly OK to use an actual image for the sprites, thus saving a couple of lines and lots of CPU power.

I'll dig up the WIP of SMB in 8k I did around your release of SMB in 14k. The Canvas based sprite generation was quite compact, more so than your base128 approach, and generated an actual image usable as CSS sprites.

@p01: Thank you. It is indeed possible to do quite a lot given the current rules of the contests, more than I had imagined. It's really just a matter of what tricks you feel comfortable doing.

Yes, I know it would've been ok to use images but it just felt like taking a step backwards now that I'd already done the JS sprite generating.

I'd be very interested to see how far you got with yours. I remember seeing the post about your 8KB version on OA and laughing when my PNG compressed version coincidentally also ended up at 8KB. The compactness of the code in the 14KB version was rather half-assed, I admit, so it'd be cool to see what an expert like you could do.

jacob,

Running in safari 3.1.2 here.

Great job, and a surprisingly challenging game (at least for me trying to get used to changing directions mid-jump with my laptop keyboard). One issue, in the third level, I fell off the first set of ? blocks (where you have 3 levels each with a ? block) to the left, and got stuck, as Mario couldn't jump high enough to get back on the ledge, and you walled off any other access. Besides that, nice work

Jacob Seidelin : Let's say I was amused by how META your approach had become :

Sprites image --> base128 DOM String mangled in JS --> JS encoded as a PNG --> load the PNG in JS, read the pixels and build a DOM String --> eval the DOM String --> which regenerate all the sprites

Theres a glitch in level three where you fall to the floor on the left side and you cant get back up

@p01: Heh, you're right, it got kinda silly. Only thing left is to do is put the PNG in a data: uri and have everything in code again. :)

@anons: Yea, don't know how I missed that.. I'm certain I placed some ?-boxes there but I guess they went missing. Fixed.

Why do you recommend ie7 or firefox 3 over safari? Afaict it works fine...

I am amazed. So where does one go to see the 20 lines of code that make this game?

http://www.nihilogic.dk/labs/20_lines_javascript/july08_super_mario/20linesofmario.js

oliver: It was just my experience that it played best in those browsers, YMMV.

That was fun for a bit. I was sad about two things though. 1.) You can't die. 2.) No music.

But still very fun and impressive.

how do I get to the negative world?

Nice. I like the fact it's kind of like an easy puzzle game Mario. Someone should develop that idea further. Good work though. Runs a little slow but playable in Firefox 3 on Leopard.

the code is longer than 20 lines

I'm counting 393 lines of code minus comments and white space. Still impressive, but somewhat misleading.

That is a m a z i n g. Hats off to you.

Works perfectly with Safara 3.1.2 as well.

Nice job, found one tiny glitch and that's the down arrow key moves the whole screen down one line for me. Don't know if that's browser specific or not.

But hey, the job was done and it works.

Good stuff

20 lines? That's incredible. The game works great and is a ton of fun :D

Just wanted to echo the great job done. At the risk of asking a question that defeats the purpose of the contest, do you have an expanded non-20 line version of the game that I could look at?

This is really good for just 20 lines! That must be some really clean condensed code. Great Job!

Learn & Review programming languages:
http://www.codesplunk.com

Though people looking at the code see more than 20 lines, it's perfectly acceptable under the imposed rules: all those lines marked as a single "line" in the comment are logically one expression or statement. There are no multiple statements per marked line so the code is perfectly acceptable as being 20-line. The way expressions are formulated it's almost like you're doing functional programming :)

Works great with Google Chrome.

do you test it on chrome??? amazing!

You are my hero!

Nice job on this amazing! :P

Thanks to a good explanation ..

Thanks to a good explanation ..

I'm trying to imagine how this is possible in 20 lines, and it's just not clicking. Even if it isn't that great, for what's there, it's amazing to be that compact.

About browsers..
IE 8: very slow. In standalone-version speed is acceptable..
Opera 10: medium speed both in full and stanalone mode.
Chrome 3: very fast and smooth! ;) but goombas don't move in Chrome!!

Conclusion: the goombas slow down Mario :)

Philip.

Dont know how i came across this but here i am playing the game 6 years later. Works great on firefox. Great job

Saz