This is maybe the single most useful extension after a password manager. I read and write lots of technical text, and it really helps to keep an overview of the terms used throughout a page. Also good for spotting typos/variations of words not in dictionaries.

One Caveat: Native Mode does not work!

not work

This could be a very useful tool if it wasn't so erratic. It is very hard to use. Highlight a word and the menu doesn't always come up or if it does, either the menu disappears before you can click on it or the highlighted text loses its highlight Nor when a word ts highlighted, does it highlight every instant of the word. If a mistake is made and you try to delete it, it removes all highlighting as well as the mistake and then the extension will not work at all. It would be helpful if there was a drp down menu on the right click. All in all, it is a very frustrating tool.
One serious problem is that if a one or two syllable word is highlighted and the same syllables appear in three or more syllable words, the one or two syllables are highlighted in words with more syllables. Example: highlight the word "sane" and the letters will be also highlighted in the word "insane."
Another problem is that if by mistake not every letter is selected in a word that is highlighted and the user later tries to correct this by selecting either the entire word or the missing letter or letters and highlight them, HIGHLIGHT ALL will highlight the missing letter(s) and split the word into two parts while highlighting all of them.
In response to an earlier comment herein about the difficulty of deleting an erroneous highlight without removing all the highlighting in the document, the app author suggested clicking on the erroneous highlight and deleting it. It doesn't work and remains a serious defect.

Great addon, thanks a lot! Can you add a hotkey to switch to the next found word? Also will be great to add ability to scroll the mouse wheel above search markers to view next founded word or press some button with mouse wheel scroll.

Oke sangat bermanfaat

Stopped working. Please fix.

please fix this, HighlightAll not working after update firefox , when i select word there is no Highlight for the same words in page
thanks for this great helpfull addons

Downloaded to get markers on my scrollbar. HighlightAll is a decent solution until Firefox makes this a standard like Chrome does. Only allows for searching of text on the page, not user input.

As I have it setup, I have to do a complicated shortcut (using the fn key to bring up f8 on my Macbook's Touchbar, so it would be nice to have the option to assign my own shortcut.

Generally good functionality, thanks Jerome.

I ahve used HighlightAll in the past, but recently it make copy a word very hard. Also, when I cannot clear the hight light neither I can't copy. Is there a fix for these problems? I have disabled it until a solution there.

Does not work anymore inside Iframes.. (Firefox 71)

Man, I love this thing. I so used to such functionality in IDEs that I added it to browser too. And now moving from chrome to firefox, this was the first extension I searched ( even before adblock). Your version does the job flawlessly and has good enough customisation

Worked up to the point of actually trying to highlight multiple words/sentences. Out of all the colors I had customized for myself only 3 worked. Then it started "crashing" and wouldn't highlight at all.

Straight-up does not work at all.

just doesnt work!.. i dont know why.. no icon the find is the same no change

Useful and easy to use.

Great tool I used

I have been liking HighlightAll in the past, BUT ,recently it has been interfering with my efforts to copy. When I try to clear the hight light, I can't copy. Is there a fix for this? I just disabled it and am waiting for a solution.

Comprends plus, auparavant (je reviens tester cet addon après quelques années) suffisait d'écrire dans google search les mots clés pour ensuite trouver toutes les occurences dans les articles, textes, etc, sans avoir à faire une seule manip, là c'est devenu une usine à gaz, et impossible de trouver un autre addon qui fasse le taf simplement.