Choose a version:
35% The original file has 267320 bytes (261.1k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 93068 bytes (90.9k, 35%).

After GZIP compression these minified files vary in size:
Microsoft
  41697 bytes (40.7k)
CDN
Boot
  38193 bytes (37.3k)
CDN
jsdelivr
  38193 bytes (37.3k)
CDN
Baidu
  33228 bytes (32.4k)
CDN
cdnjs
  33220 bytes (32.4k)
CDN
gzip -6 (default)
  33000 bytes (32.2k)
local copy
Google
  32980 bytes (32.2k)
CDN
cdnhttps
  32980 bytes (32.2k)
CDN
gzip -9
  32934 bytes (32.2k)
local copy
7zip -mx=9 -tgzip
  31886 bytes (31.1k)
local copy
kzip -s0 -rn -b1
  31854 bytes (31.1k)
local copy
libdeflate -12
  31854 bytes (31.1k)
local copy
Yandex
  31803 bytes (31.1k)
CDN
pigz -11 -n
  31792 bytes (31.0k)
local copy
Zopfli
  31782 bytes (31.0k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/jquery/jquery-1.9.0.min.js (or via HTTPS)

You will automatically get the smallest jQuery 1.9.0 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 21 bytes by using my jQuery 1.9.0 Zopfli version instead of the best available CDN (0.07% smaller than Yandex, 31782 vs. 31803 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 --mls2 --bsr7 --lazy --ohh

(found January 8, 2016)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 2  --mls2
block splitting recursion 7  --bsr7
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

Verify file integrity

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

MD5:
curl --silent --compressed https://code.jquery.com/jquery-1.9.0.min.js --location | md5sum
0652da382b6fceb033dfe2b6c06d4d11  -
curl --silent --compressed https://minime.stephan-brumme.com/files/jquery/jquery-1.9.0.min.zopfli.js.gz | md5sum
0652da382b6fceb033dfe2b6c06d4d11  -

SHA1:
curl --silent --compressed https://code.jquery.com/jquery-1.9.0.min.js --location | sha1sum
002da8cbe90fcf32fbdebb72386125079e3805ee  -
curl --silent --compressed https://minime.stephan-brumme.com/files/jquery/jquery-1.9.0.min.zopfli.js.gz | sha1sum
002da8cbe90fcf32fbdebb72386125079e3805ee  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Microsoft 41697 bytes 0652da382b6fceb033dfe2b6c06d4d11 (invalid)
Boot 38193 bytes 0652da382b6fceb033dfe2b6c06d4d11 March 18, 2015 @ 09:42
jsdelivr 38193 bytes 0652da382b6fceb033dfe2b6c06d4d11 (invalid)
cdnjs 33220 bytes 0652da382b6fceb033dfe2b6c06d4d11 (invalid)
Google 32980 bytes 0652da382b6fceb033dfe2b6c06d4d11 (invalid)
cdnhttps 32980 bytes 0652da382b6fceb033dfe2b6c06d4d11 December 24, 2015 @ 07:33
Yandex 31803 bytes 0652da382b6fceb033dfe2b6c06d4d11 June 15, 2015 @ 21:17

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Baidu 33228 bytes 2b869ea9c8edd4c2243c5d44f665f632 only whitespaces differ January 7, 2015 @ 10:16

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

Other Versions

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

3.3.1, 3.3.0,
3.2.1, 3.2.0,
3.1.1, 3.1.0,
3.0.0,
2.2.4, 2.2.3, 2.2.2, 2.2.1, 2.2.0,
2.1.4, 2.1.3, 2.1.2, 2.1.1, 2.1.0,
2.0.3, 2.0.2, 2.0.1, 2.0.0,
1.12.4, 1.12.3, 1.12.2, 1.12.1, 1.12.0,
1.11.3, 1.11.2, 1.11.1, 1.11.0,
1.10.2, 1.10.1, 1.10.0,
1.9.1, 1.9.0,
1.8.3, 1.8.2, 1.8.1, 1.8.0,
1.7.2, 1.7.1, 1.7.0,
1.6.4, 1.6.3, 1.6.2, 1.6.1, 1.6,
1.5.2, 1.5.1, 1.5,
1.4.4, 1.4.3, 1.4.2, 1.4.1, 1.4,
1.3.2, 1.3.1, 1.3,
1.2.6, 1.2.5, 1.2.4, 1.2.3, 1.2.2, 1.2.1, 1.2,
1.1.4, 1.1.3, 1.1.2, 1.1.1, 1.1,
1.0.4, 1.0.3, 1.0.2, 1.0.1, 1.0

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

Changelog

Best Zopfli parameters so far:
Size Improvement Parameters Found
31782 bytes -1 byte zopfli --i100000 --mls2 --bsr7 --lazy --ohh January 8, 2016 @ 12:19
31783 bytes -1 byte zopfli --i100000 --mls512 --bsr10 --lazy --ohh September 2, 2015 @ 00:25
31784 bytes -4 bytes zopfli --i10000 --mls512 --bsr10 --lazy --ohh September 1, 2015 @ 21:10
31788 bytes -1 byte zopfli --i1000 --mls512 --bsr10 --lazy --ohh September 1, 2015 @ 20:36
31789 bytes zopfli --i100 --mls512 --bsr10 --lazy --ohh September 1, 2015 @ 20:21

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 @ 14:37.

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
31791 31790 31798 31790 31790 31792 31792 31792 31792 31797 31786 31796 31786 31789 31799
31790 31791 31788 31790 31789 31789 31789 31788 31785 31786 31785 31785 31786 31797 31797
31788 31789 31797 31787 31790 31787 31791 31790 31787 31787 31786 31786 31789 31794 31792
31782 31783 31789 31788 31787 31788 31790 31790 31787 31789 31789 31790 31790 31790 31789
31797 31799 31786 31788 31789 31790 31789 31789 31785 31786 31788 31787 31786 31791 31797
31790 31789 31788 31788 31789 31788 31790 31790 31786 31786 31788 31789 31788 31791 31796
31788 31788 31786 31788 31787 31789 31790 31788 31783 31786 31788 31788 31789 31790 31792
31789 31788 31788 31788 31791 31791 31790 31791 31788 31786 31789 31788 31788 31793 31789
31789 31799 31797 31790 31789 31789 31790 31787 31786 31788 31783 31788 31788 31791 31798
31787 31788 31791 31788 31790 31789 31789 31791 31788 31788 31789 31789 31787 31791 31792
31788 31790 31782 31787 31791 31788 31789 31790 31787 31786 31786 31789 31789 31791 31797
31789 31800 31789 31788 31790 31790 31789 31789 31787 31789 31789 31790 31790 31791 31789
31788 31788 31782 31788 31790 31788 31790 31788 31787 31787 31789 31788 31788 31791 31790
31788 31788 31788 31788 31787 31790 31790 31787 31788 31789 31792 31789 31789 31790 31791
31789 31798 31799 31788 31789 31790 31790 31788 31786 31789 31789 31790 31790 31791 31793
31788 31788 31799 31788 31787 31789 31790 31788 31788 31787 31788 31788 31789 31791 31793
31790 31786 31798 31787 31787 31792 31789 31789 31790 31789 31789 31791 31791 31791 31793
31790 31787 31798 31788 31789 31788 31789 31789 31783 31789 31788 31791 31792 31791 31793
31789 31788 31797 31787 31787 31789 31790 31788 31788 31789 31792 31790 31790 31791 31789
31791 31798 31798 31788 31789 31790 31790 31789 31787 31789 31789 31789 31790 31791 31792
31790 31787 31798 31788 31789 31791 31790 31789 31790 31789 31790 31789 31789 31791 31798
31789 31788 31799 31788 31790 31789 31790 31788 31789 31789 31792 31789 31790 31791 31792
31789 31798 31789 31788 31791 31789 31790 31788 31791 31789 31788 31790 31791 31791 31789

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 31789 bytes 100%
1,000 31788 bytes -1 byte 100%
10,000 31784 bytes -4 bytes 100%
100,000 31782 bytes -2 bytes 17.39%
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
31856 bytes +74 bytes (+0.23%) +2 bytes
31854 bytes +72 bytes (+0.23%)
31889 bytes +107 bytes (+0.34%) +35 bytes
31926 bytes +144 bytes (+0.45%) +72 bytes
31940 bytes +158 bytes (+0.50%) +86 bytes
31965 bytes +183 bytes (+0.58%) +111 bytes
31931 bytes +149 bytes (+0.47%) +77 bytes
31955 bytes +173 bytes (+0.54%) +101 bytes
31981 bytes +199 bytes (+0.63%) +127 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 25974 bytes -5808 bytes (-18.27%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 26674 bytes -5108 bytes (-16.07%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 28336 bytes -3446 bytes (-10.84%)
Brotli (Wikipedia) brotli brotli -q 11 29520 bytes -2262 bytes (-7.12%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 29937 bytes -1845 bytes (-5.81%)
LZMA2 (Wikipedia) xz xz -9 30648 bytes -1134 bytes (-3.57%)
Zstandard (Wikipedia) zstd zstd -19 31167 bytes -615 bytes (-1.94%)

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