Choose a version:
36% The original file has 258377 bytes (252.3k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 92555 bytes (90.4k, 36%).

After GZIP compression these minified files vary in size:
Microsoft
  42141 bytes (41.2k)
CDN
Boot
  38395 bytes (37.5k)
CDN
Baidu
  33338 bytes (32.6k)
CDN
cdnjs
  33338 bytes (32.6k)
CDN
gzip -6 (default)
  33117 bytes (32.3k)
local copy
Google
  33102 bytes (32.3k)
CDN
cdnhttps
  33102 bytes (32.3k)
CDN
gzip -9
  33059 bytes (32.3k)
local copy
libdeflate -12
  32087 bytes (31.3k)
local copy
7zip -mx=9 -tgzip
  32009 bytes (31.3k)
local copy
kzip -s0 -rn -b1
  32003 bytes (31.3k)
local copy
Yandex
  31957 bytes (31.2k)
CDN
pigz -11 -n
  31941 bytes (31.2k)
local copy
Zopfli
  31915 bytes (31.2k)
local copy
Zopfli (defluff)
  31913 bytes (31.2k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/jquery/jquery-1.8.0.min.js

You will automatically get the smallest jQuery 1.8.0 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 42 bytes by using my jQuery 1.8.0 Zopfli version instead of the best available CDN (0.13% smaller than Yandex, 31915 vs. 31957 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 --mls512 --bsr15 --lazy --ohh

(found January 8, 2016)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 512  --mls512
block splitting recursion 15  --bsr15
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 2 more bytes (31913 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed http://code.jquery.com/jquery-1.8.0.min.js --location | md5sum
3a728460147fb9af7faf0e587b9fbf42  -
curl --silent --compressed http://minime.stephan-brumme.com/files/jquery/jquery-1.8.0.min.zopfli.js.gz | md5sum
3a728460147fb9af7faf0e587b9fbf42  -

SHA1:
curl --silent --compressed http://code.jquery.com/jquery-1.8.0.min.js --location | sha1sum
f3a55f44fb81cf8ee908a3872841f70d6548f8c1  -
curl --silent --compressed http://minime.stephan-brumme.com/files/jquery/jquery-1.8.0.min.zopfli.js.gz | sha1sum
f3a55f44fb81cf8ee908a3872841f70d6548f8c1  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 38395 bytes 3a728460147fb9af7faf0e587b9fbf42 March 18, 2015 @ 09:42

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Microsoft 42141 bytes cd8b0bffc85bb5614385ee4ce3596d07 only whitespaces differ (invalid)
Baidu 33338 bytes cd8b0bffc85bb5614385ee4ce3596d07 only whitespaces differ (invalid)
cdnjs 33338 bytes cd8b0bffc85bb5614385ee4ce3596d07 only whitespaces differ (invalid)
Google 33102 bytes cd8b0bffc85bb5614385ee4ce3596d07 only whitespaces differ (invalid)
cdnhttps 33102 bytes cd8b0bffc85bb5614385ee4ce3596d07 only whitespaces differ December 24, 2015 @ 07:33
Yandex 31957 bytes cd8b0bffc85bb5614385ee4ce3596d07 only whitespaces differ June 15, 2015 @ 21:17

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
31915 bytes -1 byte zopfli --i100000 --mls512 --bsr15 --lazy --ohh January 8, 2016 @ 12:19
31916 bytes -5 bytes zopfli --i100000 --mls1024 --bsr13 --lazy --ohh September 2, 2015 @ 02:07
31921 bytes -1 byte zopfli --i10000 --mls1024 --bsr13 --lazy --ohh September 1, 2015 @ 21:04
31922 bytes -3 bytes zopfli --i1000 --mls1024 --bsr13 --lazy --ohh September 1, 2015 @ 20:37
31925 bytes zopfli --i100 --mls1024 --bsr13 --lazy --ohh September 1, 2015 @ 20:23

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 @ 14:31.

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
31943 31935 31943 31944 31943 31944 31942 31947 31948 31939 31941 31931 31933 31930 31943
31930 31926 31934 31934 31934 31935 31934 31933 31933 31935 31937 31926 31928 31927 31938
31933 31932 31931 31923 31927 31930 31924 31934 31927 31922 31923 31926 31927 31930 31926
31930 31929 31927 31928 31931 31928 31933 31934 31923 31935 31922 31924 31927 31929 31923
31927 31929 31928 31932 31932 31928 31925 31934 31933 31927 31924 31933 31929 31930 31935
31931 31931 31931 31931 31933 31929 31934 31934 31933 31933 31926 31925 31928 31927 31934
31927 31932 31928 31929 31931 31931 31924 31934 31933 31927 31926 31928 31928 31930 31925
31931 31927 31927 31924 31933 31934 31932 31934 31933 31926 31926 31924 31928 31926 31934
31935 31928 31932 31937 31934 31933 31923 31933 31933 31935 31925 31925 31928 31930 31920
31931 31928 31928 31930 31931 31929 31924 31934 31925 31916 31924 31925 31929 31929 31926
31931 31927 31924 31929 31931 31930 31924 31933 31934 31935 31926 31927 31929 31927 31934
31928 31929 31928 31923 31931 31929 31932 31934 31915 31934 31925 31924 31927 31930 31934
31930 31928 31923 31923 31931 31929 31925 31934 31933 31925 31925 31923 31928 31929 31925
31927 31927 31923 31923 31931 31930 31930 31934 31933 31933 31926 31932 31929 31926 31923
31927 31927 31927 31932 31931 31930 31933 31934 31933 31933 31926 31924 31928 31930 31924
31927 31927 31927 31923 31931 31928 31927 31933 31934 31933 31926 31926 31928 31929 31927
31929 31928 31926 31931 31934 31929 31934 31933 31925 31926 31925 31926 31928 31929 31929
31930 31928 31929 31924 31932 31929 31925 31933 31933 31926 31924 31923 31928 31927 31928
31928 31928 31923 31924 31927 31927 31933 31933 31933 31925 31922 31926 31928 31928 31926
31927 31927 31924 31924 31928 31928 31929 31934 31933 31935 31924 31924 31929 31928 31922
31927 31928 31929 31925 31931 31928 31930 31933 31933 31933 31925 31924 31929 31928 31923
31928 31927 31928 31923 31932 31928 31929 31934 31933 31926 31920 31925 31928 31929 31923
31927 31927 31923 31923 31931 31930 31924 31934 31922 31935 31925 31926 31927 31930 31926

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 31924 bytes 100%
1,000 31921 bytes -3 bytes 100%
10,000 31917 bytes -4 bytes 100%
100,000 31915 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
32003 bytes +88 bytes (+0.28%)
32003 bytes +88 bytes (+0.28%)
32032 bytes +117 bytes (+0.37%) +29 bytes
32065 bytes +150 bytes (+0.47%) +62 bytes
32066 bytes +151 bytes (+0.47%) +63 bytes
32098 bytes +183 bytes (+0.57%) +95 bytes
32101 bytes +186 bytes (+0.58%) +98 bytes
32099 bytes +184 bytes (+0.58%) +96 bytes
32127 bytes +212 bytes (+0.66%) +124 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 25598 bytes -6317 bytes (-19.79%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 26453 bytes -5462 bytes (-17.11%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 28162 bytes -3753 bytes (-11.76%)
Brotli (Wikipedia) brotli brotli -q 11 29462 bytes -2453 bytes (-7.69%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 29509 bytes -2406 bytes (-7.54%)
LZMA2 (Wikipedia) xz xz -9 30628 bytes -1287 bytes (-4.03%)
ZSTD (Wikipedia) zstd zstd -19 31312 bytes -603 bytes (-1.89%)

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