Firefox Extension: HTML Entity Character Lookup

Remy Sharp wrote a web service to look up HTML Entity Character. The service “allows you to quickly find the entity based on how it looks”. There is also an OpenSearch plugin and MacOS Dashboard widget. Kudos to Remy!

I figured a Firefox extension clone would be handy, and it wouldn’t be too difficult to make one, thus:

This extenion is simple: a GUI wraps and calls the Javascript code Remy wrote (with a little modifiication, basically renaming global variables to make them unique) and then displays the result. The code is licensed under Creative Commons by-sa 2.5, same as Remy’s code.

It should work on Firefox from version 1.5 and above (have tested on 3.0aPre7 too), also on Netscape Navigator and Flock, let me know if you have any problem using it.

To try out, go to the extension’s home page and click install (it’s currently hosted on my server, so you have to let Firefox allow download and install extension from my server).

I could have made the extension remotely invoke Remy’s web service, parse the return html and present the result, but it might not be a good option, because:

  1. I need it work while off-line (too much distraction online);
  2. HTML entities character set doesn’t change that often, what’s the last addition? € maybe?
  3. Overhead from network traffic and CPU cycles parsing html;
  4. Not really a reason though: I could later make use of the new Online and Offline Events and provide user the options;

Update (09/09/2008):
You should be able to have it run on Firefox 3.0.1 and above.

25 Responses to “Firefox Extension: HTML Entity Character Lookup”

  1. Remy Says:

    Great work – thanks!

    I’ve added a link in the features of the HTML entities linking back your extension.

  2. Yining Says:


    Very gload to be able to contribute :-)

  3. Roger Says:

    Nice extension !! :)

    However, I couldn’t figure out how to emulate the “Include extended character sets in search” feature from the online service (which is also amazing)…

    Eg.: how could I found ă ?



  4. Yining Says:

    Hi Roger,

    It seems Remy’s online service is not able to find ă as well (as already pointed out by someone else). So I have the same question as Remy did: where can I find the entity code list that contains those characters? It would be great if I can add them in.

    Thanks :)

  5. Roger Says:

    Hi Yining,

    First of all, sorry for taking too long to reply…

    Remy’s online service is able to find ă (code 259).
    Turn on the “Incl. extended” option and enter “259″ code.



  6. Yining Says:

    Hi Roger,

    Yes, it was an oversight of me.

    I have made a new build, please upgrade the installed extension. I will make some enhancement on the user interface later, but the search now should return the extended chars.

    Thank you very much for the help!

    Yining :-)

  7. Roger Says:


    I’ve installed the new version… Now it is fine !! :)

    Regarding the enhancement on the UI, I have one suggestion: could you make the dialog resizable ?

    I have plenty of vertical space on my desktop… and been able to read the entire description would be a good thing (horizontal space).

    And no… *I* thank you for this extension… :)


  8. Yining Says:


    Just found out that on Windows the extension window is not resizable, (I am using linux and it’s been resizable since day one…), so this defect wasn’t noticed before :-(

    Now the new release(0.1.3) should be resizable and remember the window position, width and height. Hope it meets your needs :)



  9. Roger Says:


    Amazing !! The resizable feature is ok now… :D

    Thanks again,


  10. Biscuitrat Says:

    Wonderful extension! I love the HTML entity lookup already, but having it as an extension is so much handier! Thank you :D

  11. TWSStopper可以下载了 - Yining.write() Says:

    [...] 这是我自己边学边写的第一个Firefox扩展(之前发布的HTML Entity Char Lookup其实是第二个),因为一直断断续续在开发,因此用的一直是本地目录(Firefox支持开发和测试时候,扩展使用解压后的独立目录)的形式,没有直接打包成可直接安装的xpi文件; [...]

  12. waterbee Says:

    版本 0.1.4 與 Firefox 3.0.1 RC1 不相容
    (The version 0.1.4 is incompatible with Firefox 3.0.1 RC1)

  13. Bennett Says:

    thanks for this very useful extension. Could you add the ability to simply copy the character itself? Just add a third option, “Copy Character”, to the context menu.

    For example, if I want to type the character for “one half”, I go to Remy’s site and enter “1/2″. I ignore the entity code and numeric code and simply copy the character ½. If your excellent extension could do this too then it would be even more useful.

  14. Yining Says:

    Hi Bennett,

    Thanks for the kind words, I will try to get this request implemented one of these few days.

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  16. HTML Entity character lookup | Michel Hiemstra - Web Development & Internet Marketing Says:

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  17. _mark Says:

    not working in FF 3.5 yet. anyone have time?

  18. Alex R. Says:

    hi there! i was wondering if you could update this extension to work in firefox 3.5.* or later.

  19. Chris Says:

    AddOn does not work with Firefox 3.5.3!

  20. Philipp Schaffner Says:

    I would appreciate a port to FF3.5.x as well!

  21. Daniel Says:

    hi there,

    what a pity… it even doesn’t work with firefox version 3.6.3 :(

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