Choose a version:
26% The original file has 312194 bytes (304.9k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 81520 bytes (79.6k, 26%).

After GZIP compression these minified files vary in size:
Boot
  31888 bytes (31.1k)
CDN
cdnjs
  27747 bytes (27.1k)
CDN
cdnhttps
  27734 bytes (27.1k)
CDN
gzip -6 (default)
  27649 bytes (27.0k)
local copy
gzip -9
  27615 bytes (27.0k)
local copy
7zip -mx=9 -tgzip
  26452 bytes (25.8k)
local copy
kzip -s0 -rn -b6
  26416 bytes (25.8k)
local copy
libdeflate -12
  26410 bytes (25.8k)
local copy
pigz -11 -n
  26392 bytes (25.8k)
local copy
Zopfli
  26287 bytes (25.7k)
local copy
Zopfli (defluff)
  26286 bytes (25.7k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/dojo/dojo-1.3.3.min.js

You will automatically get the smallest Dojo 1.3.3 file, ETag caching is available and
if your browser doesn't support GZIP decompression then the uncompressed version will be sent.

Currently best Zopfli settings

Save 1447 bytes by using my Dojo 1.3.3 Zopfli version instead of the best available CDN (5.50% smaller than cdnhttps, 26287 vs. 27734 bytes):
You can use my super-compressed files for whatever purpose you like as long as you respect the library's original license agreement.
There are no restrictions from my side - but please avoid hot-linking if you run a high-traffic website.

These command-line settings yielded the best compression ratio so far (Linux version of zopfli-krzymod):
zopfli --i100000 --mb8 --mls128 --bsr21 --lazy --ohh

(found December 2, 2015)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 128  --mls128
block splitting recursion 21  --bsr21
lazy matching in LZ77 yes  --lazy
optimized Huffman headers yes  --ohh
initial random W for iterations 1  --rw1
initial random Z for iterations 2  --rz2

Even Smaller Files Thanks To Defluff

Zopfli's output can be further optimized by the defluff tool.
In this particular case, defluff saves 1 more byte (26286 bytes).

Verify file integrity

After decompression, my uncompressed files are identical to the original ones:

MD5:
curl --silent --compressed http://download.dojotoolkit.org/release-1.3.3/dojo.js --location | md5sum
5d50de0574b44e79df9a9cd8b4b6686a  -
curl --silent --compressed http://minime.stephan-brumme.com/files/dojo/dojo-1.3.3.min.zopfli.js.gz | md5sum
5d50de0574b44e79df9a9cd8b4b6686a  -

SHA1:
curl --silent --compressed http://download.dojotoolkit.org/release-1.3.3/dojo.js --location | sha1sum
97e561dfeb842c21b35e6f9963914316221cca1d  -
curl --silent --compressed http://minime.stephan-brumme.com/files/dojo/dojo-1.3.3.min.zopfli.js.gz | sha1sum
97e561dfeb842c21b35e6f9963914316221cca1d  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 31888 bytes 5d50de0574b44e79df9a9cd8b4b6686a March 19, 2015 @ 15:30
cdnjs 27747 bytes 5d50de0574b44e79df9a9cd8b4b6686a February 8, 2015 @ 14:45

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
cdnhttps 27734 bytes 56b21462e2f676cd22ce7f37deae4d19 < /*
< Copyright (c) 2004-2009, The Dojo Foundation All Rights R [...]
< Available via Academic Free License >= 2.1 OR the modifie [...]
< see: http://dojotoolkit.org/license for details
< */
<
< /*
< This is a compiled version of Dojo, built for deployment [...]
< development. To get an editable version, please visit:
<
[...]
December 24, 2015 @ 07:33

Note: only the MD5 hashes are shown to keep things simple.

Other Versions

Available Dojo versions at minime.stephan-brumme.com:

1.13.0,
1.12.3, 1.12.2, 1.12.1,
1.11.5, 1.11.4, 1.11.3, 1.11.2, 1.11.1, 1.11.0,
1.10.9, 1.10.8, 1.10.7, 1.10.6, 1.10.5, 1.10.4, 1.10.3, 1.10.2, 1.10.1, 1.10.0,
1.9.11, 1.9.10, 1.9.9, 1.9.8, 1.9.7, 1.9.6, 1.9.5, 1.9.4, 1.9.3, 1.9.2, 1.9.1, 1.9.0,
1.8.12, 1.8.11, 1.8.10, 1.8.9, 1.8.8, 1.8.7, 1.8.6, 1.8.5, 1.8.4, 1.8.3, 1.8.2, 1.8.1, 1.8.0,
1.7.10, 1.7.9, 1.7.8, 1.7.7, 1.7.6, 1.7.5, 1.7.4, 1.7.3, 1.7.2, 1.7.1, 1.7.0,
1.6.3, 1.6.2, 1.6.1, 1.6.0,
1.5.4, 1.5.3, 1.5.2, 1.5.1, 1.5.0,
1.4.6, 1.4.5, 1.4.4, 1.4.3, 1.4.2, 1.4.1, 1.4.0,
1.3.3, 1.3.2, 1.3.1, 1.3.0,
1.2.3

The project site contains an overview how well these versions were compressed.
Other interesting projects are AngularJS, BackboneJS, Bootstrap, D3, Ember, jQuery, Knockout, lodash, React, Socket.IO, ThreeJS, UnderscoreJS and Vue.

Changelog

Best Zopfli parameters so far:
Size Improvement Parameters Found
26287 bytes -1 byte zopfli --i100000 --mls128 --bsr21 --lazy --ohh December 2, 2015 @ 08:51
26288 bytes -1 byte zopfli --i10000 --mls128 --bsr21 --lazy --ohh December 2, 2015 @ 08:10
26289 bytes -2 bytes zopfli --i10000 --mls64 --bsr21 --lazy --ohh September 23, 2015 @ 21:05
26291 bytes -2 bytes zopfli --i1000 --mls64 --bsr21 --lazy --ohh September 23, 2015 @ 20:28
26293 bytes -4 bytes zopfli --i1000 --mls64 --bsr13 --lazy --ohh September 14, 2015 @ 21:33
26297 bytes -4 bytes zopfli --i1000 --mls512 --bsr13 --lazy --ohh September 11, 2015 @ 02:18
26301 bytes -4 bytes zopfli --i1000 --mls512 --bsr8 --lazy --ohh September 11, 2015 @ 02:12
26305 bytes zopfli --i100 --mls512 --bsr13 --lazy --ohh September 10, 2015 @ 15:03

If there are multiple parameter sets yielding the same compressed size, only the first one found is shown.

Most recent activity on June 16, 2016 @ 14:36.

Heatmaps

This Zopfli heatmap visualizes how compression changes when modifying the --bsr and --mls parameter.
Cell's contents is the best filesize achieved (in bytes, hover with mouse over cells to see number of iterations).

Good parameters are green, bad are red. The best and worst are bold as well.
The brightness of the blue background color indicates how many iterations were processed:
10,000 or 100,000.
bsr \ mls
2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384 32768
bsr \ mls
2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384 32768
26364 26369 26371 26371 26354 26377 26376 26380 26378 26367 26371 26374 26366 26372 26375
26338 26353 26303 26313 26338 26332 26365 26303 26312 26366 26371 26375 26372 26377 26369
26337 26349 26322 26327 26325 26345 26374 26371 26370 26370 26374 26372 26380 26369 26364
26345 26340 26348 26348 26338 26336 26374 26325 26293 26373 26365 26370 26371 26365 26368
26319 26354 26310 26292 26337 26339 26302 26299 26296 26365 26374 26371 26369 26368 26372
26341 26341 26318 26341 26340 26332 26303 26371 26295 26371 26366 26365 26372 26366 26366
26341 26340 26339 26332 26295 26328 26333 26303 26302 26365 26363 26371 26368 26371 26365
26338 26333 26338 26331 26316 26292 26312 26305 26298 26363 26363 26367 26370 26370 26366
26332 26324 26311 26327 26329 26328 26297 26371 26296 26364 26364 26365 26366 26370 26366
26329 26351 26338 26314 26309 26289 26288 26323 26293 26364 26364 26362 26382 26376 26366
26345 26340 26340 26320 26331 26292 26293 26299 26298 26364 26363 26364 26381 26369 26367
26356 26341 26344 26308 26312 26333 26293 26322 26293 26364 26365 26371 26380 26366 26364
26341 26343 26346 26313 26337 26296 26301 26302 26305 26363 26364 26372 26374 26369 26370
26344 26335 26346 26315 26339 26313 26325 26313 26302 26363 26363 26367 26374 26366 26365
26331 26340 26343 26338 26335 26310 26335 26328 26296 26364 26363 26366 26301 26368 26366
26341 26339 26341 26313 26337 26348 26294 26371 26293 26365 26371 26369 26371 26369 26364
26343 26333 26302 26331 26331 26337 26304 26312 26302 26364 26363 26371 26369 26370 26366
26341 26341 26338 26337 26340 26289 26287 26329 26295 26365 26364 26370 26368 26369 26366
26355 26309 26331 26342 26341 26342 26368 26371 26373 26372 26375 26367 26381 26365 26365
26341 26339 26339 26332 26291 26327 26326 26302 26293 26363 26363 26365 26369 26366 26364
26351 26308 26350 26327 26291 26330 26295 26370 26371 26372 26364 26365 26372 26366 26365
26340 26333 26341 26326 26330 26328 26295 26294 26300 26387 26366 26362 26377 26369 26366
26339 26338 26345 26342 26334 26332 26308 26292 26295 26364 26364 26364 26381 26371 26365

Due to the Monte Carlo design of my search algorithm, not all parameters have reached the same number of iterations yet:
Iterations Min. Bytes Reduction Coverage
100 26301 bytes 100%
1,000 26291 bytes -10 bytes 100%
10,000 26288 bytes -3 bytes 100%
100,000 26287 bytes -1 byte 0.58%
1,000,000
10,000,000

KZIP has far less options available for tuning/optimization. I only played around with the number of blocks (parameter -n):
Blocks Min. Bytes Compared To Best Zopfli Compared To Best KZIP
26419 bytes +132 bytes (+0.50%) +3 bytes
26419 bytes +132 bytes (+0.50%) +3 bytes
26437 bytes +150 bytes (+0.57%) +21 bytes
26422 bytes +135 bytes (+0.51%) +6 bytes
26455 bytes +168 bytes (+0.64%) +39 bytes
26432 bytes +145 bytes (+0.55%) +16 bytes
26416 bytes +129 bytes (+0.49%)
26422 bytes +135 bytes (+0.51%) +6 bytes
26469 bytes +182 bytes (+0.69%) +53 bytes

Non-DEFLATE Algorithms

Archivers based on completely different compression algorithms often produce superior results.
Unfortunately, browsers only support gzip compression at the moment.
Algorithm Program Parameters Size Compared To Best Zopfli
ZPAQ (Wikipedia) zpaq zpaq -method 69 21302 bytes -4985 bytes (-18.96%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 23362 bytes -2925 bytes (-11.13%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 24233 bytes -2054 bytes (-7.81%)
Brotli (Wikipedia) brotli brotli -q 11 24392 bytes -1895 bytes (-7.21%)
LZMA2 (Wikipedia) xz xz -9 25300 bytes -987 bytes (-3.75%)
ZSTD (Wikipedia) zstd zstd -19 25916 bytes -371 bytes (-1.41%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 26111 bytes -176 bytes (-0.67%)

Detailled Analysis

I wrote a DEFLATE decoder in Javascript. Click the button below to start a client-side analysis of the smallest gzipped files (may take a second):


Notes: pigz is a fast open source multi-threaded implementation of gzip written by one of the original authors of gzip.
However, when using compression level 11, pigz actually switches to the slower Zopfli algorithm and isn't multi-threaded anymore.
KrzyMOD's extensions to Zopfli offer the highest level of configuration and is therefore used for my brute-force search.
Ken Silverman wrote the closed-source KZIP compression program and Jonathon Fowler ported it to Linux.
Defluff was created by Joachim Henke; DeflOpt is a tool by Ben Jos Walbeehm.

website made by Stephan Brumme in 2015 and still improving in 2018.
all timestamps are displayed in central european time. see my changelog.
no flash, not even images or external css files - and everything squeezed into a single html file.
which was handsomely compressed before releasing it into the wild internet - obviously.

please visit my homepage and my blog, too.
email: minime (at) stephan-brumme.com