209 reviews for this add-on
  • In order to make it work in FF14 I had to reinstall Firebug, restart browser, disable Yslow, restart browser, then re-enable Yslow and restart one more time.
  • It does not work on Firefox 14.0.1 with Firebug 1.10.0, on Windows Vista 32bits. When I click YSlow, it just shows blank box. When I click Run YSlow, nothing happen, and close when I click Close. It just only works to close. The old version (both YSlow and FF, I don't know exactly which version) is working well in the past. I noticed that problem since last week when my FF and YSlow automatically updated. Now, I'm using Google Page Speed plugin and it works very fine. Sorry guys, you should fix this asap. I like YSlow and I would like to continue to use it anymore.
  • I installed FF14.01 again... Firebug 1.10.0 and the latest Yslow 3.1.3.... Icon is there... but when I click on Yslow... see nothing... gray bar... and left Run Yslow and close... but that's it...

    Problem solved: deinstall Yslow and then Firebug, restarted FF. Installed Firebug, the Yslow, restarted FF again.
    Then I had the same problem: I opened Yslow... gray bar... clicked on the Firebug icon... and then suddenly the
    Yslow appeared in the bar of Firebug again... closed the Yslow gray bar... and now its works as usual...
    Can you please give me more details about your environment?
  • Works great with FF 14 and Firebug 1.1

    Need to follow instructions to get it working with FF 9. About:Config entry needs to be named "extensions.checkCompatibility.9.0" as a boolean set to "False"

    Side note: It didn't work at first with the above config entry but I then added a similar entry ending with "14.0" instead of "9.0" then reinstalled Firebug 1.1 (Yslow already installed) and Yslow started working again. Oddly, the entry ending in "14.0" is no longer on the About:Config list but the "9.0" is still there. Go figure...
  • One of the best addons for Firebug.

    Sadly does not work with the latest version of firebug 1.10.0 on firefox 14.0.1
  • Awesome Add-on for a web developer.
    It is my second most used add-on after firebug.
    Not good place for bug reporting, but I have similar problem to Shirish.
    On Win 7 64bit
    FF 14.0.1
    Firebug 1.10.0
    Yslow 3.1.3
    All other add-ons disabled
    YSlow does not appear as tab in Firebug.
    Btn on add-on bar opens window with Run Yslow link (does not work) and Close link (does close).
    Same behavior on machine with
    XP 32 bit
    FF 14.0.1
    Firebug 1.10.0
    Yslow 3.1.3
    All other add-ons disabled.
    Love your add-on, I panic when it goes away occasionally.

    Update: All working after downgrade to Firebug 1.9.2
  • YSlow got disable even on installing again after updating Firebug to 1.1.10 for Firefox 14.
    Hi, just updated my FF and seems to be working fine:
    Firefox 14
    Firebug 1.10.0
    YSlow 3.1.2
    Can that be any other conflicting addon?
  • Awesome tool
  • Brilliant tool. Highly recommended.
  • Does not work with Firebug 1.10 . Works with Firebug 1.09 . Firefox version 13.0.1
    Sorry for the inconvenience, YSlow 3.1.2 is now compatible with latest Firebug 1.10.0. Thanks for your patience.
  • Yslow addon is very useful to check our web page size and load time. This is very useful to increase the grade of webpage.
  • Great tool for testing website speed. I have one wish, to have separate results for third party files (like from google, facebook, twitter, etc) because I can't do a thing about them, they clutter up YSlow reports and make it hard for me to see the things that are actually fixable on my websites.
  • Thanks for the update of such a wonderful decision as YSlow!
    Many thanks to plug-in developer.
  • the test version YSlow 3.0.9 works fine with FireBug 1.9.0
    scroll down to "Version Information >> see complete version history".
  • Spent Hours Trying To Get It To Work -
    Searched Countless Pages For Help -
    SHoneT. Opened My Chrome Browser -
    No Problemo.................
    Well There Is One Small Problem.........
    No Tools Tab !!!!
  • Doesn't work on FF9.

    Please help!
  • Doesn't work.
    Firefox 9.0.1
    Firebug 1.9.0
    YSlow 3.0.4
  • Damn! Not work for my FF 9!!
  • I tried upping the max version to 10 in the .rdf file but it still would not work for me.

    Then found that a YSlow bookmarklet is available: http://developer.yahoo.com/yslow/mobile/#javascript:%28function%28y,p,o%29{p=y.body.appendChild%28y.createElement%28%27iframe%27%29%29;p.id=%27YSLOW-bookmarklet%27;p.style.cssText=%27display:none%27;o=p.contentWindow.document;o.open%28%29.write%28%27%3Chead%3E%3Cbody%20onload=%22YUI_config={win:window.parent,doc:window.parent.document};var%20d=document;d.getElementsByTagName%28\%27head\%27%29[0].appendChild%28d.createElement%28\%27script\%27%29%29.src=\%27http://d.yimg.com/jc/yslow-bookmarklet.js\%27%22%3E%27%29;o.close%28%29}%28document%29%29
  • A great tool but quit working with Firefox 9.01 and Firebug 1.9. Please fix.
  • Excelente complemento.
    Lástima que no funciona en FF 9, debo emplear Utilu Mozilla Firefox Collection y ejecutar Mozilla 3.6 con el complemento para medir mis sitios.
  • Guys,

    YSlow is never working with FF5. Since, its a best tool for web-developers like me, Pls try to do something to make this best tool to work as best as ever.

    Mohan Siva
  • Me parece excelente este material de trabajo
  • For those desperate to make this work in FF8, it is possible to edit the 6.* field in the install.rdf file and change the 6 to 8 (or higher). It's not recommended - you need to know what you are doing and if you mess up you could bork Firefox - but YSlow seems to work fine.

    Yahoo just need to find someone who can change the 6 to an 8... Must be tight over there these days. :)
  • Loved it when it worked but still down after a month? Cannot go back in Firefox it seams so noSlow.