Smooth Scrolling Now Available in Mozilla Nightly Builds

Tuesday March 25th, 2003

Thanks to the fix for bug 174049, the latest Mozilla nightly builds now support IE-style smooth scrolling. This feature is disabled by default. To enable it, use about:config to add the boolean preference general.smoothScroll with a value of true. To disable smooth scrolling, simply set the value of the pref to false. If you're not sure how to modify hidden preferences using about:config then you'll want our handy new guide, How To Modify Hidden Preferences Using about:config.

#1 How do you delete a preference?

by flloyd

Tuesday March 25th, 2003 7:24 PM

The guide at tells you how to add and edit a preference but not how to delete one. I entered a preference incorrectly and am not able to delete it. Can I only do this manually?

#2 Re: How do you delete a preference?

by AlexBishop

Tuesday March 25th, 2003 7:28 PM

"I entered a preference incorrectly and am not able to delete it. Can I only do this manually?"

The Reset option will generally neutralise a pref's affect. I think the only when to remove it entirely is by editing prefs.js by hand. It would probably be really dangerous to let users remove arbitary prefs from a GUI.


#15 removing prefs vs. changing them

by djk

Wednesday March 26th, 2003 7:23 AM

Removing prefs via the GUI is somehow worse than being able to arbitrarily change them in the GUI?

I thought about:config was for power users anyways...

#16 Re: removing prefs vs. changing them

by mlefevre

Wednesday March 26th, 2003 8:20 AM

I don't think there's any particular "safety" concern.

there is a bug open on removing prefs in about:config, but the prefs backend code doesn't make it possible to do it - once you set a pref, it stays set as something (even if that something is blank) until you close mozilla. however, if you right click and "reset" a pref that's not normally there, it won't get saved in prefs.js and will disappear from the about:config list after you've closed and opened the browser.

there's no functional difference between resetting a pref to default and removing it from the list - it's just a quirk of the way things are displayed.

#30 Oh, OK

by djk

Thursday March 27th, 2003 6:40 AM

I haven't messed with 'resetting' a pref and then looking to see when/if it disappears from prefs.js.

Thanks for the clarification.

#48 Fixing a goofed smoothScroll setting

by Skyzyx

Thursday July 3rd, 2003 8:18 PM

I accidentally set general.smoothScroll as a string instead of a boolean. I tried resetting and recreating the pref, but even if I create a new boolean general.smoothScroll, the string one stays. I can't find prefs.js on my Windows system to edit, otherwise I would.

#3 Not as smooth as IE

by drfickle

Tuesday March 25th, 2003 9:39 PM

But it's a start any way. Keep up the great work!

#11 An alternative

by DeepFreeze3

Wednesday March 26th, 2003 2:32 AM

As a substitute, you could go to Edit - Preferences - Advanced - Mouse Wheel and modify your settings to scroll a document by more than 3 lines. I set it at 10. It works perfectly for me.

#4 feedback

by neil

Tuesday March 25th, 2003 10:04 PM

hi all, I'm the original developer of the smooth scrolling patch. I've seen a lot of comments such as "not as smooth as x", "still a little jagged", etc. I don't have a lab of computers to test this patch on, so if you have any constructive criticism, please try to be as concrete as possible, i.e., "doesn't scroll far enough", "images render slowly when scrolling", etc.

I know that it's not simple to break down scrolling into these discrete components, but it's really the only way this feature will get better.


#13 Re: feedback (Sweeet)

by joe222

Wednesday March 26th, 2003 5:19 AM

I didn't find any issues with it until I read this thread and compared with IE.

1. In IE scrolling with the wheel mouse seems to follow the setting of how many scroll lines to scroll down with the wheel. This makes it at times, like within this text box I'm using to write this message, a bit too slow as it is set up in mozilla... it takes too many rolls of the wheel mouse to just get to the top or bottom of the box... could also be done to the behaviour I see of this feature when getting to the top or bottom of a page, that it slows down, so in a tiny box like the one I'm now it's pretty slow. 2. When clicking in the arrows to scroll (in the scrollbar), in IE, it follows the same setting of scrolling 3 lines (my setting), in Mozilla it scrolls depending of how long you press, in really smooth chuncks. This is not necessarily bad, but... I use that to go sometimes just a few lines up... would be better if it would go the chunk set in the scrolling option in windows... or, to cover for other OS's sport that setting in mozilla itself (defaulting to the OS's when available) 3. With the touchpad, the driver has a feature to glide as if you used the scroll wheel, the behaviour is more erratic. It seems it doesn't read often enough from the touchpad input. It somehow stops at times... don't know how to explain that better, hope it helps, though :) In IE I can... dance up and down, always following with extreme smoothness my movements on the touchpad. Not as much in Moz.

Other than that the scroll feature would be nice to be a default setting. People who complain are the ones who will have an easier time setting it off if they don't like it. The other way around is not true. And a setting in preferences like IE has to set smooth scrolling would go a long way to make the change even easier.

And finally, a great job. I find it amazingly comfortable. It just keeps making this browser better and better. Thanks! :)

#46 Possible replacement for smooth scroll.

by avih

Thursday April 17th, 2003 5:53 AM

There's an extension that can enhance/replace smoothscroll. it's also working on older browsers. has 6 presets and lots of configurations. it also has optimized code.

#14 Re: feedback (found a possible bug)

by joe222

Wednesday March 26th, 2003 5:37 AM

Just notice that there is leftover (artifacts) left on the page on smooth scrolling (need to check if it does without the s/s on):

On viewing a bug in bugzilla, like and smooth scroll enabled...

After "Description Opened: 2002-10-11 17:58" there is a ruler. After it the initial post for a bug is shown and then the remaining... scroll with the wheel mouse/scrollbar buttons one at a time (i.e. slowly) until the ruler just dessapears from the viewport at the top. Go back once, so it's again in view. See the artifacts??

A dot or couple of dots appear just under the ruler in each of it's sides.

Thought I would mention it in case it's related ;) If it's not and no one can point to a bug that deals with this, I will submit the bug later today or tomorrow.

#25 Is smooth scroll implemented on MacOS X?

by PaulB

Wednesday March 26th, 2003 7:33 PM

I have never used IE on the Mac or Windows so I may misunderstand what smooth scroll is. Maybe someone can provide a short explanation of smooth scroll.

I added the preference to turn on smooth scroll. Honestly I do not see any difference with smooth scrolling on or off. BTW I am using the trunk build from March 26 Build ID 2003032609.

#42 Excellent, Excellent, Excellent

by adinas

Wednesday April 2nd, 2003 3:07 AM

Just tried it out and it works great. This was one the advantages that IE had for me up to now.

Now i can finally enjoy scrolling in Mozilla. it is a pleasure.

#44 Re: feedback

by itsayellow

Thursday April 3rd, 2003 5:25 PM

I like the idea of smooth scrolling. Page up and page down look really nice. I just have one request to make it work a little better:

I like to hold down up-arrow or down-arrow to fine-scroll through a page. The smooth scrolling behavior on my win2k pc / moz1.4a seems to be a little strange when I do this. While I hold down the arrow key, scrolling seems really sluggish. But if I let up on the arrow key after holding it down for a while the page scrolls fast for a split second afterward.

What I'd like to see is smooth scroll start up scrolling smoothly, but then scroll at the normal speed while my finger is down on the arrow. Then slow down to a stop as quickly as possible once I let up on the arrow key. The fast scroll after letting up on the arrow key is a little disconcerting.

#45 Re: feedback

by jhatax

Monday April 7th, 2003 2:32 PM

There seems to be a bug in the smooth-scroll feature. If I scroll up or down with the Mouse Wheel too fast, CPU usage goes up to a 100% and the windows becomes unresponsive. After maybe 5 seconds, CPU usage goes back to normal (6-7%) and the page continues scrolling.

OS: Win XP SP 1 Browser: Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; 5) Gecko/20030402 Mozilla/0.5

#5 why God why?!<RANT>

by Down8

Wednesday March 26th, 2003 12:34 AM

I know this isn't constructive, and will definitely get some disagreement, but...

Why the hell would we want the _WORST_"FEATURE"_EVER_ , from IE, into our beloved Moz? Smooth scrolling the bane of my existence, especially in labs where I can't change it. I cna find no redeeming quality in SS, and I don't know anyone (with a modicum of techno-savvy) who leaves it enabled on IE.

Sorry for the rant, -bZj

#6 Re: why God why?!<RANT>

by michaelH

Wednesday March 26th, 2003 12:53 AM

That's why it's disabled by DEFAULT

I don't like it either personally, but I understand that some people do like it. Each to their own I say

#7 Re: why God why?!<RANT>

by totalxsive

Wednesday March 26th, 2003 1:08 AM

I personally like the feature. It's one of the (few) things I miss from IE.

#8 I wonder why, too. So if you like it, explain why?

by huggie

Wednesday March 26th, 2003 1:26 AM

I didn't know that was actually a "feature" until I read this column. I don't know if I'm getting this right. But if smooth scrolling also means one click in the arrow button resulting in various scrolling length according to the content, then I must say that I don't like this feature. It makes the amount of scrolling unpredictable and thus annoying. So would people explain to me why this feature is favorable please. Pleasing to the eye? For me if there is a smooth yet predicatable scrolling then it's great.

#9 Re: why God why?!<RANT>

by peterlairo

Wednesday March 26th, 2003 2:08 AM

Well, I think smoth scrolling is great! I only wished it were ON by default. It is MUCH easier on the eyes to follow a page that is scolling by smoothly than one that is jumping by in spurts.

Oh sarm, I just realized that you offered NO facts whatsoever, and therefore your post was pure TROLLING. I just wasted my time! :(

#18 Talkback data

by ruudd

Wednesday March 26th, 2003 8:57 AM

well here are some facts: smooth scrolling is not pleasant to the eyes because you still can't follow it, SS is slow and when you want it to stop it doesn't (well in IE, did not try it with moz), if you know that you want to look at the bottom of a page you cannot scroll: it takes hours to 'smoothly' get there!

that said, I think it is great to have this feature for all those people out there who like it so much, but it is even better to have it disabled by default! because personally I cannot think of anybody who wants it, only thos who don't know that it can be turned of so they learned to life with it.

so if you dont like the scrolling in spurts, well configure your scrolling better! mine is: only wheel, 3 lines; shift and wheel, 1 page if you can control your finger, than this is very pleasant!

#26 Re: why God why?!<RANT>

by astrosmash

Wednesday March 26th, 2003 8:24 PM

I agree that smooth scrolling in IE (and Windows in general) is totally brutal. Given the relatively poor quality of some recent feature additions, like type-ahead-find and auto-image-shinkage, I was ready to join you in registering my disgust throughout the internet, but after actually trying Mozilla's smooth scrolling, I must say I am pleasantly surprised; Impressed even. It's really done very well; It's very responsive to the mouse wheel, and doesn't over-scroll or bog things down, unlike IE.

In fact, I think I'm going to leave it turned on for a while. Hats off to Neil Cronin!

#28 RE: type-ahead-find

by TimHunt

Thursday March 27th, 2003 3:22 AM

> Given the relatively poor quality of some recent feature additions, like type-ahead-find ...

Type-ahead find? poor-quality? are you mad???

I was a bit sceptical about TAF at first, but now I could not live without it.

The place where it is a real killer-feature is for any programming documentation. etc.

Just start typing the thing you want to look up, and you are straight there.

I am amazed that such a simple little feature can be so useful.


#34 Re: RE: type-ahead-find

by jwb

Saturday March 29th, 2003 12:39 PM

TAF is rather poorly done. The difference between finding a link and finding plain text is very difficult for the user to understand. But the main problem is that TAF is totally unreliable. Often TAF refuses to find something, even when I plainly see it on the page! In these cases the normal find will find it, but not TAF. Argh.

#32 Re: Re: too bad

by simifilm

Friday March 28th, 2003 12:47 AM

I don't understand what you have against find as you type. IMO this is Moz's most useful feature besides tabs. Whenever I have to use another browser than Moz I catch myself trying to do it I got so used to it.

#43 Reading long documents was a nightmare until now

by adinas

Thursday April 3rd, 2003 8:39 AM

I kept losing my place whenever i scrolled. I don't understant why some people hate it

#10 Yeah, but ...

by DeepFreeze3

Wednesday March 26th, 2003 2:29 AM

On one hand, smooth scrolling is in. On the other, the ability to turn off the "Open a link in a new window" option (in NS 7.02, it's in Edit - Preferences - Advanced - Scripts & Plugins) can't be turned on or off. Hell, it's not even in the UI anymore. Without it, the popup supression function can't really function effectively. It's not like anybody was shoving it down users throats. People did have a choice as to whether to turn it on or not. And all because a certain somebody decided to whine about it. He should've done a better job of reading the Help menu, instead of making the rest of us suffer for it. This truly sucks.

#12 Re: Yeah, but ...

by sunfire

Wednesday March 26th, 2003 2:41 AM

I used this feature, but I thought this is now covered by the pop-up blocking function. I've set pop-up blocking to "suppress popups" (which as far as I've seen so far does the same as the old scripting option). I only have a few pages where I need popups enabled and I just added them to the list of sites which are allowed to use pop-ups.

#21 Do a Singapore on this guy!! :-)

by DeepFreeze3

Wednesday March 26th, 2003 12:22 PM

No, it's not. If this option isn't there, clicking on links can bring up whole new windows. ARRGHH!! Somebody should find out whoever the hell is responsible for this and cane his ass 45 times with a wet bamboo stick.

#22 Re: Yeah, but ...

by Sander

Wednesday March 26th, 2003 12:40 PM

You know... either you're a very good troll, or you're a very stupid person. I distinctly recall explaining to you in a thread why the _checkbox_ for this feature was removed _for the time being_ for various good reasons, but that the feature itself is present as always, and that you can enable it by setting user_pref("browser.block.target_new_window", true);

Yet from all that I wrote, you seem to have picked up only what you wanted to see...

Aaah, why do I bother...

#27 SNIFF, SNIFF ... Do I smell a troll named Sander?

by DeepFreeze3

Thursday March 27th, 2003 2:27 AM

Why do you bother? Maybe a no life-having a**hole like yourself needs an activity to keep himself occupied until those favorite after midnight jerkoff movies on Cinemax that he likes so much come on? You know? The ones that have those fat, ugly lesbians in them with the stretch marks on their asses? ;-)

Again, that piece of sh*t you call a brain missed the point entirely: Users shouldn't have to be penalized because some ninny has the ability to bitch & moan loudly enough. Nobody was forcing anyone to use this function. Users had the option of turning it on or off. They had a choice. Why the hell should we have to go into the bowels of some prefs.js file to get back an option that should be there in the first place? If that guy didn't like the function, fine. Turn it off and don't use it. Nobody should have to make us do brain surgery on our browsers to get it back because some guy was too damn lazy to get into the help menu.

Don't you have anything better to do than fling out the word "troll" whenever somebody posts something that you don't like? Oh, that's right!! You're one yourself!! ;-) STUNAD!! Get a new trick, dufus!! This one is getting SO boring!! ZZZZZZZZZZ!!!

PS: I don't read anything you post. They're stupid. Plus, I don't want to fall asleep in front of my computer.

BTW: You can now feel free to post another one of your lame assed "I'm a troll" messages. You have no life. How sad.

#17 I'm sorry,..

by Assimil8or

Wednesday March 26th, 2003 8:39 AM

.. but I have no idea what smooth scrolling is... can someone explain this to me?

#19 Re: I'm sorry,..

by mlefevre

Wednesday March 26th, 2003 10:03 AM

if you have a long web page on the screen, and click the scrollbar (or use the keyboard) to jump down a page, then usually mozilla will just jump immediately to showing the new part of the page. with smooth scrolling enabled, the new part of the page will scroll onto the screen from the bottom instead of just appearing.

probably the best thing is to try using it...

#20 Re: I'm sorry,..

by MXN

Wednesday March 26th, 2003 10:51 AM

With normal scrolling, the page content just jumps suddenly when you push the arrow keys. With smooth scrolling, the content slides. It's supposed to be easier on the eyes, but I've been so used to normal scrolling that smooth scrolling gives me a headache.


#23 Ok, thx...

by Assimil8or

Wednesday March 26th, 2003 1:18 PM

.. Never noticed that there was a difference in the scrolling between IE and Mozilla.

#24 BTW, when talking about nice ie features ...

by jobe451

Wednesday March 26th, 2003 2:47 PM

... when does ie, konqueror or phonix like autocompletition of forms arrive to mozilla?

#29 Re: BTW, when talking about nice ie features ...

by coda

Thursday March 27th, 2003 5:25 AM

Edit > Preferences > Privacy & Security > Forms

Or am I missing something?

#31 BTW, when talking about nice ie features ...

by jobe451

Thursday March 27th, 2003 1:56 PM

Edit > Preferences > Privacy & Security > Forms is something, but for sure nothing useful. check out how ie does autocompletition, mozilla is far from anything that easy...

#33 smoothwheel (similar to smoothscroll) as extension

by avih

Saturday March 29th, 2003 10:51 AM

I've made this extension before the mozilla implementation of smoothscroll was released, but by the time i set up the mozdev account, i was was a bit late ;).

short comparision between my smoothwheel and mozilla's smoothscroll:

advantages over smoothscroll: - works well with older versions (every version that i tested) on phoenix, mozilla, on win32/linux. - configurable (linearity and duration) via javascript variables. - timer operation: will always finish scrolling when 'time's up', thus will be smoother on more powerfull computers, while will NOT take forever on slower computers.

disadvantages in comparision with smoothscroll: - only working on browser window. - incomplete detection of target object (forms, some images). - no handling of Up/Dn/PgUp/PgDn keys (easily implementable though).

regardless of the disadvantages, I find it quite usable, and pleasant to work with.

check it out on

hope you enjoy it. cheers avih

#41 autoscroll from mozdev

by mdtam

Wednesday April 2nd, 2003 1:19 AM

avih, have you tried autoscroll from mozdev? give it a try...

#35 scroll step

by cyd

Saturday March 29th, 2003 5:04 PM

smoothScroll works very nicely for me, except for one thing: the step size is too small. With smoothscroll on, stepping up or down should move the document by a larger amount, since the movement is easier to follow. I estimate that the step size should be doubled.

Does anyone know if it's possible to tweak the step size (say in about:config)?

#36 yes, possible

by avih

Saturday March 29th, 2003 11:29 PM

it's configurable via mozilla configuration panel, on the wheelmouse page. the default is 3 lines per wheel event. you can change that to 5 or 10 if you prefere.

#37 Re: scroll step

by neil

Sunday March 30th, 2003 12:15 AM

Scrolling by larger increments is definitely in the works. The main goal for the first patch was to get it working and tested, which has happened. Unfortunately, it's not straight-forward to just "scroll more" for when smooth scrolling is turned on. I'm working on it.

#38 Re: Re: scroll step

by avih

Sunday March 30th, 2003 3:25 AM

Neil, can you pls go to smoothwheel page on and email me? thanx avih

#39 Re: scroll step

by neil

Sunday March 30th, 2003 9:11 AM

I don't have a mouse.

#40 Re: scroll step

by mdtam

Wednesday April 2nd, 2003 1:12 AM

Neil/Avih, et al.

You guys should take a look at autoscroll ( ) . I've been using it for a while and it's really cool. I'd be interested in seeing and comparing it with smoothwheel, smoothscrolling, etc.

autoscroll differs in that you click the middle mouse btn / mouse wheel on a page and jerking you mouse "up" scrolls the page upward. Similarly for the downward direction ; IE has something similar.

I wonder how many others have used autoscroll... It's been on mozdev for a while...

-- Tommy Tam

#47 Re: 1997-98 When NSCP 4.x was the hype...

by avih

Wednesday April 30th, 2003 7:16 PM

@mdtam: yes i know, and use it daily (through all in one gestures). however, there's nothing to compare. smoothscroll/wheel is NOT autoscroll. they complement each other rather than compete...