YSlow Version History

31 versions

Be careful with old versions!

These versions are displayed for reference and testing purposes. You should always use the latest version of an add-on.

Version 3.1.8 201.1 kB Works with Firefox 3.0 and later

minor left-tabs compat issue w/ latest firebug update

Version 3.1.7 201.1 kB Works with Firefox 3.0 and later

fixed issue with latest firebug 1.12

Version 3.1.4 199.7 kB Works with Firefox 3.0 and later

Fixed Firebug init issue

Version 3.1.3 199.7 kB Works with Firefox 3.0 and later

Version 3.1.2 200.7 kB Works with Firefox 3.0 and later

Compatible with Firebug 1.10.0
Updated Twitter bird and username
Updated Scoremeter URL
Updated CDN list

Version 3.1.0 196.6 kB Works with Firefox 3.0 and later

Version 3.0.9 194.6 kB Works with Firefox 3.0 and later

Bug fix for latest stable Firefox 9, beta 10 and aurora 11 on Firebug 1.9.0.
Patch fix provided by Adrian Yee (GTMetrix) via exceptional-performance@yahoogroups.com

Version 3.0.4 212.0 kB Works with Firefox 3.0 and later

Version 3.0.4
-------------
* Fixed Firebug issues:
* FirebugContext removed from latest versions
* Broken "Run Test" button
* Custom CDN loading during initalization
* Fixed empty page when clicking tools on FF5/Win
* New feature: one-click-add-cdn to CDN custom list

Version 3.0.3 210.9 kB Works with Firefox 3.0 and later

This is the next-gen YSlow version for Firefox.

Version 3.0.3
-------------------

* Added CDN checking from HTTP headers: Server and X-CDN (currently: cloudflare)
* Added Social support: Sharing YSlow results through Twitter and Facebook
* Like (Facebook) and Follow (Twitter) links on help menu

Version 2.1.0 226.3 kB Works with Firefox 3.0 and later

  • Compatible with latest Firefox 3.6, as well as Firefox 4 Beta

  • Compatible with Firebug 1.6 beta

  • Updated JSLint version (2010-09-16)

  • Improved error message display (removed pop-up, using console instead for error message)

  • Fixed some infinite loops issues for redirects and some autorun weird behavior

  • Added new rule for detecting empty src or href (, , and ) as suggested in Nicholas Zakas' NCZOnline

  • Added logic to not consider deferred scripts on head as offenders — previous version of YSlow complains when scripts tags are inserted dynamically into the HEAD tag. Such scripts do not block page rendering and are downloaded in parallel with other resources

  • Fixed inconsistency in displaying Expires date inside YSlow report Summary View column

  • Fixed “JavaScript at bottom rule” issue — previous version of YSlow complains when scripts tags are inserted dynamically into the HEAD tag, now it doesn't consider dynamically injected scripts into HEAD

  • Fixed issue running JSLint from a page loaded from a previous about:blank

Version 2.0.7 220.2 kB Works with Firefox 3.0 - 3.6.*

* Encode URI components in beacon parameters.
* For CDN rule, add the list of offending components in beacon parameters.

Version 2.0.6 220.2 kB Works with Firefox 3.0 - 3.6.*

Fix crash on startup in Firefox 3.6.

Version 2.0.2 216.1 kB Works with Firefox 2.0 - 3.5.*

Version 2.0.1 215.0 kB Works with Firefox 2.0 - 3.5.*

- Replace setTimeout() calls with nsITimer to address security vulnerability of setTimeout.
- Replace eval() calls with evalInSandbox to comply with security advisory.
- Modify CDN lint function to make the comparison more efficient.
- Refactor jslintwrapper.

Version 2.0.0b6 214.0 kB Works with Firefox 2.0 - 3.5.*

- Moved jsmin, js_beautify, JSON and JSLINT in YSLOW namespace.

Version 2.0.0b4 203.8 kB Works with Firefox 2.0 - 3.5.*

Version 2.0.0b4 is certified to work with Firefox 3.5 and Firebug 1.4b5.

Known Issue
----------------
1. Opening the Firebug panel may sometimes require a refresh of the page if Autorun is disabled. We are actively addressing this.

Version 2.0.0b3 203.8 kB Works with Firefox 2.0 - 3.0.*

Version 2.0.0b2 203.8 kB Works with Firefox 2.0 - 3.0.*

Version 2.0.0b1 203.8 kB Works with Firefox 2.0 - 3.1b3

Version 1.0.2 86.0 kB Works with Firefox 1.5 - 3.1b2

Various bug fixes.

Version 1.0.1 86.0 kB Works with Firefox 1.5 - 3.1b2

- Firefox 3.1b2 support
- Added JavaScript beautification/unminification feature under "Tools"
- Improved support for max-age cache control headers
- Misc bug fixes

Version 0.9.5b2 81.9 kB Works with Firefox 1.5 - 3.0.*

* Firefox 3 and Firebug 1.2 beta support
* improved and simplified check for javascript minification
* different coloring for inline vs external CSS and JS ("All CSS" and "All JS" features)
* clickable list of resources as a Table of Contents ("All CSS" and "All JS" features)
* improved colors and presentation in the "legend" of component pies under Stats
* fixed a bug where the same hostname with different port number was counted as a separate DNS lookup.
* misc bugfixes and style tweaks

Version 0.9.5b1 80.9 kB Works with Firefox 1.5 - 3.0b5

* Firefox 3 beta 5 support
* Support for the latest versions of the different Firebug branches - 1, 1.1. and 1.2
* Graph representation of the components in the Stats tab
* Improved display in the expanded CSS expressions rule report (Performance tab)
* Misc fixes for the reports in the Tools section
* Works with NetPanel disabled (default behavior in Firebug 1.2)

Version 0.9.4 79.9 kB Works with Firefox 1.5 - 3.0b4pre

* Fixed a conflict with the Tab Mix Plus extension
* Fixed an issue with components that are not in the DOM and also Firebug cannot access their headers

Version 0.9.3 80.9 kB Works with Firefox 1.5 - 3.0b4pre

* Firefox 3 support
* Beacons (images with dimensions 1x1 that are not part of the DOM) excluded from the overall score
* Sortable components in the Components tab
* Fixed misc bugs that caused YSlow to freeze as it peels off the page (encountering streams, applets, empty urls)

Version 0.9.2 76.8 kB Works with Firefox 2.0 - 2.0.0.*

* Detect non-DOM requests (XHRs, image beacons, etc.) by extracting from Net Panel.
* Crawl frames and iframes to find components.
* Highlight 4xx response codes in Components View.
* Display thumbnails when hover over image URLs
* Implement search within YSlow Firebug panel.
* Add "doc" and "xhr" to the list of components to check for gzip compressions.
* Bug fix: Improve detection of CSS expressions (ignore rules that contain the word "expression").
* Bug fix: Change status bar colors to work with dark Firefox themes.
* Bug fix: Do not penalize for DNS lookups if the hostname is already an IP address.
* Bug fix: Don't include components with data:, javascript:, and chrome: protocols.
* Bug fix: Better detection of JS minification for "/* */" style comments.
* Bug fix: Display all unique filenames when more than one script file is included multiple times.

Version 0.9.0 76.8 kB Works with Firefox 2.0 - 2.0.0.*

* Detect non-DOM requests (XHRs, image beacons, etc.) by extracting from Net Panel.
* Crawl frames and iframes to find components.
* Highlight 4xx response codes in Components View.
* Display thumbnails when hover over image URLs
* Implement search within YSlow Firebug panel.
* Add "doc" and "xhr" to the list of components to check for gzip compressions.
* Bug fix: Improve detection of CSS expressions (ignore rules that contain the word "expression").
* Bug fix: Change status bar colors to work with dark Firefox themes.
* Bug fix: Do not penalize for DNS lookups if the hostname is already an IP address.
* Bug fix: Don't include components with data:, javascript:, and chrome: protocols.
* Bug fix: Better detection of JS minification for "/* */" style comments.
* Bug fix: Display all unique filenames when more than one script file is included multiple times.

Version 0.9.1 76.8 kB Works with Firefox 2.0 - 2.0.0.*

* Detect non-DOM requests (XHRs, image beacons, etc.) by extracting from Net Panel.
* Crawl frames and iframes to find components.
* Highlight 4xx response codes in Components View.
* Display thumbnails when hover over image URLs
* Implement search within YSlow Firebug panel.
* Add "doc" and "xhr" to the list of components to check for gzip compressions.
* Bug fix: Improve detection of CSS expressions (ignore rules that contain the word "expression").
* Bug fix: Change status bar colors to work with dark Firefox themes.
* Bug fix: Do not penalize for DNS lookups if the hostname is already an IP address.
* Bug fix: Don't include components with data:, javascript:, and chrome: protocols.
* Bug fix: Better detection of JS minification for "/* */" style comments.
* Bug fix: Display all unique filenames when more than one script file is included multiple times.

Version 0.8.0 107.5 kB Works with Firefox 2.0 - 2.0.0.*

* Patch Firebug's Net Panel to not show resources read from cache (with no HTTP traffic).
* Fix bug where stylesheets in the head with mixed case filenames were not recognized.
* Make the message about specifying CDN hostnames more prevalent.

Version 0.7.1 106.5 kB Works with Firefox 2.0 - 2.0.0.*

* New option to hide the YSlow info in the statusbar.
* Better logic for detecting when ETags have a bad format (Rule 13).
* Added ability to open links in new tab or new window with a right-click, and left click follows the user's preference.
* Recognize deflate in addition to gzip for Rule 4.
* Fix bug so now you can right-click on https and ftp component URLs in the Performance view.
* Better handling of XHR failures when we try to find the components in the page.