Choose a version:
43% The original file has 180459 bytes (176.2k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 77746 bytes (75.9k, 43%).

After GZIP compression these minified files vary in size:
Microsoft
  33710 bytes (32.9k)
CDN, direct link
Boot
  30920 bytes (30.2k)
CDN, direct link
Baidu
  27038 bytes (26.4k)
CDN, direct link
cdnjs
  26938 bytes (26.3k)
CDN, direct link
gzip -6 (default)
  26796 bytes (26.2k)
local copy
Google
  26776 bytes (26.1k)
CDN, direct link
cdnhttps
  26776 bytes (26.1k)
CDN, direct link
gzip -9
  26765 bytes (26.1k)
local copy
7zip -mx=9 -tgzip
  25931 bytes (25.3k)
local copy
libdeflate -12
  25910 bytes (25.3k)
local copy
Yandex
  25872 bytes (25.3k)
CDN, direct link
pigz -11 -n
  25865 bytes (25.3k)
local copy
kzip -s0 -rn -b4
  25853 bytes (25.2k)
local copy
Zopfli
  25837 bytes (25.2k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/jquery/jquery-1.4.3.min.js

You will automatically get the smallest jQuery 1.4.3 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 35 bytes by using my jQuery 1.4.3 Zopfli version instead of the best available CDN (0.14% smaller than Yandex, 25837 vs. 25872 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 --mls4096 --bsr19 --lazy --ohh

(found January 7, 2016)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 4096  --mls4096
block splitting recursion 19  --bsr19
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 http://code.jquery.com/jquery-1.4.3.min.js --location | md5sum
e4958bd2e32d9fcd6115a585ed17a9cc  -
curl --silent --compressed http://minime.stephan-brumme.com/files/jquery/jquery-1.4.3.min.zopfli.js.gz | md5sum
e4958bd2e32d9fcd6115a585ed17a9cc  -

SHA1:
curl --silent --compressed http://code.jquery.com/jquery-1.4.3.min.js --location | sha1sum
97be02d1785b7bb4f41ae116a6a9bef74cb018d6  -
curl --silent --compressed http://minime.stephan-brumme.com/files/jquery/jquery-1.4.3.min.zopfli.js.gz | sha1sum
97be02d1785b7bb4f41ae116a6a9bef74cb018d6  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Microsoft 33710 bytes e4958bd2e32d9fcd6115a585ed17a9cc (invalid)
Boot 30920 bytes e4958bd2e32d9fcd6115a585ed17a9cc March 18, 2015 @ 09:41
cdnjs 26938 bytes e4958bd2e32d9fcd6115a585ed17a9cc (invalid)
Google 26776 bytes e4958bd2e32d9fcd6115a585ed17a9cc (invalid)
cdnhttps 26776 bytes e4958bd2e32d9fcd6115a585ed17a9cc December 24, 2015 @ 07:33
Yandex 25872 bytes e4958bd2e32d9fcd6115a585ed17a9cc June 15, 2015 @ 21:17

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Baidu 27038 bytes 2e5c0bbe6054db97a4c62c10d0019aa9 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:

3.2.1, 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
25837 bytes -2 bytes zopfli --i100000 --mls4096 --bsr19 --lazy --ohh January 7, 2016 @ 16:55
25839 bytes -3 bytes zopfli --i100000 --mls4096 --bsr14 --lazy --ohh September 2, 2015 @ 01:18
25842 bytes -2 bytes zopfli --i10000 --mls4096 --bsr14 --lazy --ohh September 1, 2015 @ 21:21
25844 bytes -3 bytes zopfli --i1000 --mls4096 --bsr14 --lazy --ohh September 1, 2015 @ 20:39
25847 bytes zopfli --i100 --mls2048 --bsr14 --lazy --ohh September 1, 2015 @ 20:28

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 @ 14:34.

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
25849 25848 25849 25852 25855 25848 25846 25848 25849 25859 25860 25858 25849 25848 25853
25853 25846 25851 25851 25843 25853 25847 25853 25848 25855 25851 25842 25849 25843 25845
25845 25851 25847 25851 25847 25850 25853 25852 25844 25845 25843 25845 25842 25845 25845
25846 25846 25844 25852 25845 25851 25851 25852 25846 25845 25849 25846 25843 25843 25843
25844 25844 25851 25851 25842 25844 25853 25842 25845 25853 25842 25848 25843 25843 25843
25845 25846 25851 25851 25843 25854 25851 25852 25847 25853 25842 25842 25843 25841 25843
25845 25845 25847 25850 25843 25843 25854 25843 25847 25851 25845 25844 25845 25843 25842
25846 25846 25851 25851 25842 25851 25851 25843 25846 25856 25845 25844 25841 25843 25844
25847 25846 25851 25852 25842 25852 25854 25851 25849 25846 25844 25842 25844 25843 25843
25844 25846 25855 25854 25843 25852 25853 25852 25843 25853 25851 25844 25844 25842 25843
25846 25846 25851 25846 25842 25851 25854 25843 25846 25854 25843 25839 25842 25844 25843
25846 25846 25851 25855 25851 25852 25853 25852 25847 25853 25844 25842 25843 25843 25843
25846 25846 25847 25853 25844 25842 25851 25852 25847 25853 25842 25844 25842 25844 25843
25846 25846 25853 25853 25851 25851 25851 25852 25847 25853 25846 25842 25843 25844 25843
25846 25844 25851 25854 25842 25851 25854 25852 25846 25851 25851 25842 25844 25844 25843
25846 25846 25851 25852 25843 25842 25854 25852 25847 25854 25843 25837 25845 25850 25842
25853 25853 25851 25851 25851 25851 25851 25841 25848 25853 25845 25849 25850 25842 25842
25845 25844 25845 25852 25843 25852 25852 25842 25846 25851 25844 25844 25844 25846 25844
25844 25846 25853 25850 25844 25852 25854 25841 25847 25853 25843 25844 25843 25843 25843
25846 25846 25851 25852 25842 25849 25843 25852 25846 25853 25844 25842 25843 25843 25845
25847 25846 25848 25845 25843 25849 25853 25852 25846 25851 25843 25842 25844 25841 25843
25846 25846 25845 25854 25851 25842 25853 25852 25846 25853 25843 25844 25845 25842 25845
25846 25846 25851 25853 25842 25851 25854 25852 25846 25853 25845 25843 25844 25843 25842

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 25846 bytes 100%
1,000 25843 bytes -3 bytes 100%
10,000 25839 bytes -4 bytes 100%
100,000 25837 bytes -2 bytes 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
25942 bytes +105 bytes (+0.41%) +89 bytes
25942 bytes +105 bytes (+0.41%) +89 bytes
25949 bytes +112 bytes (+0.43%) +96 bytes
25896 bytes +59 bytes (+0.23%) +43 bytes
25853 bytes +16 bytes (+0.06%)
25866 bytes +29 bytes (+0.11%) +13 bytes
25908 bytes +71 bytes (+0.27%) +55 bytes
25922 bytes +85 bytes (+0.33%) +69 bytes
25953 bytes +116 bytes (+0.45%) +100 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 21272 bytes -4565 bytes (-17.67%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 21863 bytes -3974 bytes (-15.38%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 22848 bytes -2989 bytes (-11.57%)
Brotli (Wikipedia) brotli brotli -q 11 23938 bytes -1899 bytes (-7.35%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 24622 bytes -1215 bytes (-4.70%)
LZMA2 (Wikipedia) xz xz -9 25080 bytes -757 bytes (-2.93%)
ZSTD (Wikipedia) zstd zstd -19 25520 bytes -317 bytes (-1.23%)

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 2017.
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