Choose a version:
26% The original file has 623532 bytes (608.9k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 161818 bytes (158.0k, 26%).

After GZIP compression these minified files vary in size:
gzip -6 (default)
  54706 bytes (53.4k)
local copy
gzip -9
  54655 bytes (53.4k)
local copy
libdeflate -12
  52003 bytes (50.8k)
local copy
7zip -mx=9 -tgzip
  51994 bytes (50.8k)
local copy
pigz -11 -n
  51969 bytes (50.8k)
local copy
kzip -s0 -rn -b1
  51950 bytes (50.7k)
local copy
Zopfli
  51859 bytes (50.6k)
local copy
Zopfli (defluff)
  51858 bytes (50.6k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/dojo/dojo-1.9.8.min.js (or via HTTPS)

You will automatically get the smallest Dojo 1.9.8 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

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 --mls16 --bsr21 --lazy --ohh

(found March 25, 2016)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 16  --mls16
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 (51858 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed https://download.dojotoolkit.org/release-1.9.8/dojo.js --location | md5sum
62b6dfc6162a6b34cea712ae3109f73e  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.9.8.min.zopfli.js.gz | md5sum
62b6dfc6162a6b34cea712ae3109f73e  -

SHA1:
curl --silent --compressed https://download.dojotoolkit.org/release-1.9.8/dojo.js --location | sha1sum
7ca01c19699bcb634288e191d905140542f72c71  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.9.8.min.zopfli.js.gz | sha1sum
7ca01c19699bcb634288e191d905140542f72c71  -

Other Versions

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

1.14.2, 1.14.1, 1.14.0,
1.13.3, 1.13.2, 1.13.1, 1.13.0,
1.12.4, 1.12.3, 1.12.2, 1.12.1,
1.11.6, 1.11.5, 1.11.4, 1.11.3, 1.11.2, 1.11.1, 1.11.0,
1.10.10, 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,
1.8.14, 1.8.13, 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,
1.7.12, 1.7.11, 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
51859 bytes -2 bytes zopfli --i100000 --mls16 --bsr21 --lazy --ohh March 25, 2016 @ 10:39
51861 bytes -9 bytes zopfli --i100000 --mls2 --bsr30 --lazy --ohh March 24, 2016 @ 14:30
51870 bytes -1 byte zopfli --i10000 --mls2 --bsr30 --lazy --ohh March 24, 2016 @ 13:05
51871 bytes -6 bytes zopfli --i10000 --mls16 --bsr15 --lazy --ohh March 24, 2016 @ 11:39
51877 bytes -4 bytes zopfli --i1000 --mls32 --bsr18 --lazy --ohh March 24, 2016 @ 11:19
51881 bytes zopfli --i100 --mls16 --bsr9 --lazy --ohh March 24, 2016 @ 11:05

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
51877 51876 51876 51875 51878 51877 51873 51875 51871 51891 51894 51891 51893 51894 51895
51875 51874 51875 51874 51873 51892 51888 51882 51876 51888 51886 51884 51892 51887 51877
51888 51884 51884 51875 51874 51883 51884 51881 51878 51885 51883 51882 51886 51888 51881
51883 51874 51883 51909 51873 51861 51884 51872 51879 51877 51876 51883 51883 51880 51892
51883 51886 51872 51871 51873 51871 51873 51871 51886 51889 51883 51882 51888 51888 51887
51886 51885 51871 51871 51871 51875 51873 51881 51879 51888 51876 51887 51885 51881 51879
51874 51881 51872 51871 51873 51875 51873 51880 51879 51889 51892 51883 51888 51882 51892
51874 51871 51885 51871 51873 51872 51884 51872 51878 51887 51885 51883 51887 51887 51888
51875 51876 51873 51871 51874 51873 51874 51872 51879 51887 51885 51885 51889 51878 51888
51886 51883 51881 51872 51873 51884 51872 51880 51879 51887 51893 51890 51886 51888 51885
51872 51875 51871 51871 51874 51873 51875 51872 51873 51885 51889 51881 51885 51881 51883
51873 51881 51875 51871 51882 51883 51871 51874 51879 51885 51886 51883 51884 51893 51891
51881 51883 51882 51874 51872 51875 51872 51873 51885 51885 51883 51887 51886 51881 51888
51873 51883 51871 51871 51871 51874 51873 51873 51886 51890 51885 51882 51889 51884 51887
51883 51882 51882 51871 51871 51885 51873 51875 51878 51890 51877 51885 51886 51891 51886
51883 51883 51882 51874 51871 51875 51884 51880 51879 51887 51884 51881 51888 51881 51886
51886 51883 51874 51872 51871 51871 51874 51871 51880 51880 51885 51882 51887 51877 51887
51873 51875 51873 51859 51873 51873 51872 51881 51879 51888 51889 51883 51884 51881 51890
51880 51883 51872 51871 51873 51885 51872 51880 51879 51887 51877 51884 51883 51882 51887
51874 51882 51884 51872 51874 51880 51884 51872 51878 51890 51883 51881 51887 51881 51883
51882 51882 51882 51860 51873 51885 51873 51881 51879 51889 51877 51881 51884 51881 51887
51861 51877 51882 51872 51874 51871 51884 51880 51871 51889 51885 51882 51888 51882 51880
51884 51881 51872 51871 51873 51873 51874 51875 51871 51884 51885 51892 51887 51882 51891

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 51881 bytes 100%
1,000 51877 bytes -4 bytes 100%
10,000 51870 bytes -7 bytes 100%
100,000 51859 bytes -11 bytes 1.16%
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
52028 bytes +169 bytes (+0.33%) +78 bytes
51950 bytes +91 bytes (+0.18%)
51962 bytes +103 bytes (+0.20%) +12 bytes
51996 bytes +137 bytes (+0.26%) +46 bytes
52028 bytes +169 bytes (+0.33%) +78 bytes
52072 bytes +213 bytes (+0.41%) +122 bytes
52083 bytes +224 bytes (+0.43%) +133 bytes
52117 bytes +258 bytes (+0.50%) +167 bytes
52105 bytes +246 bytes (+0.47%) +155 bytes

Non-DEFLATE Algorithms

Archivers based on completely different compression algorithms often produce superior results.
Unfortunately, browsers only support gzip compression at the moment.
However, support for Brotli is constantly growing - but your browser doesn't support it.
Algorithm Program Parameters Size Compared To Best Zopfli
ZPAQ (Wikipedia) zpaq zpaq -method 69 38253 bytes -13606 bytes (-26.24%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 45606 bytes -6253 bytes (-12.06%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 46465 bytes -5394 bytes (-10.40%)
Brotli (Wikipedia) brotli brotli -q 11 47870 bytes -3989 bytes (-7.69%)
LZMA2 (Wikipedia) xz xz -9 48972 bytes -2887 bytes (-5.57%)
Zstandard (Wikipedia) zstd zstd -19 50443 bytes -1416 bytes (-2.73%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 50696 bytes -1163 bytes (-2.24%)

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