I'm working on a site with lots of CSS3 transitions (which are hardware accelerated) and high memory objects (for example, an array of 39 objects, each containing the full html source for a typical online news article) and I'm noticing some very choppy/jittery scrolling, which I've been unable to debug.
I've kept these high memory objects out of the DOM, which should prevent them from affecting DOM performance, however, I can't help but think that they are still having a negative effect. I don't have code samples to post because I'm unsure of whether this is even an issue.
Please go to this site (Orange) and click on an article tile. In the reader div that pops up over the page, try scrolling as you normally would. Does it feel choppy/jittery? Do you have any suggestions on how to improve this?
CSS3 transitions, opacity, text and box-shadows and the like are certainly known to impact rendering speeds. In fact, even sites with heavy use of text-shadow alone can cause choppy scrolling on the average computer. Combining this with heavy use of javascript seems like a recipe for choppy web browsing.
edit: The loading animation on the o in orange is pretty awesome!
Yes, that's jittery. A page with a lot of Javascript will do that and frameworks like jQuery won't help at all. I'd recommend recoding as much as you can without using jQuery and passing it through JSLint (http://www.jslint.com/).
Try using Chrome's developer tools too to get an idea of what the bottleneck is.
Try disabling Javascript too and seeing if it's any better. If it isn't, then you know where your problem lies.
Related
IE6+ got some problems with transition as usual but i know ways to get trough those but the thing im wondering if i use flash instead of getting nerfed by transition lacks would it make my website better or lamer? Cause if i use .swf files even for smallest animations i guess it would drop the performance really badly but would look better. Essipecially while im using opacity transition.
So which would be better to use on IE6+ or What would u expect from a website while browsing with IE6+? A good looking .swf with a performance lack or a crappy looking transition with good performance?
get ie6 out of your mind. Take a look at the percentage share of people using ie6...
http://www.w3schools.com/browsers/browsers_explorer.asp
1.2% in november and december 2011!
Quit supporting it!
I’m building a mobile web application, and even though I’m still in a prototyping kind of the process, I’m having a hard time fixing certain performance problems.
The application itself (works all smooth in desktop browsers, but significantly sluggish in Mobile Safari): Hancards webapp prototype. You may login as mifeng:wangwang or create a new user.
The overall clumsy performance could be tolerable though, except for one thing: the browser simply crashes (!) when you open a set page, tap ‘view’ (enlarge all cards) and then try to go back to the previous page.
The code that gets executed when ‘view’ is tapped is this (very sluggish by itself as well; any way to improve it?):
if ($(this).hasClass('big')) {
$('.card').unwrap().removeClass('big flippable').addClass('small');
$(this).removeClass('big');
}
else {
$('.card').wrap('<div class="bigCardWrap" />').removeClass('small').addClass('big flippable');
$(this).addClass('big');
}
And another thing, a pretty weird bug. Very often the ‘word of the day‘ block won’t display the text node for the last element (<div class="meaning">), even though it’s in the code. The text will not show unless you ‘shake’ the DOM anyhow (unticking and ticking back one of the associated CSS properties can also achieve that). This happens in both desktop and mobile Safari browsers.
The code that writes it in there is this:
// While we are here, also display the Word of the day
$.post('ajax.php', {action: 'stuff:showWotd'}, function(data) {
// Decode the received data
var msg = decodeResponse(data);
// Insert the values
$('.wotd .hanzi').text(msg.content[0]['hanzi']);
$('.wotd .pinyin').text(msg.content[0]['pinyin']);
$('.wotd .meaning').text(msg.content[0]['meaning']);
});
I don’t expect you to advice me on how to fix the performance of the whole application (I will probably have to revise the overall scope of the project instead of trying to find workarounds), but I at least would like to see how to solve these two problems. Thank you!
The only performance issue I see in the script is the wrap/unwrap calls - adding and removing elements from the DOM tends to be fairly slow, and you can probably get the same effect by always having a wrapper element and changing its class rather than adding or removing it.
However, the performance issues you are seeing are most likely in your css:
3D transforms can be much faster than 2D due to hardware acceleration. It looks like you already have this, though you do need to be careful about which elements it is applied to
Shadows have real performance issues, especially when animated. Removing them will probably fix most of the slowness.
Rearranging background images can help - A single background image under transparent pages is faster than having a background image for each page.
I am making digital instruments for a car. These instruments will be constantly updated by information through ajax. These instruments will be served from a server onboard the vehicle through WLAN (fast) to my iPhone 3G. Is imperative to the success of the project that the updating of the tachometer is smooth and very responsive. Otherwise, it will look retarded.
The first problem I encountered was when I made this demo where tachometer moves quickly back and forth between zero and a thousand RPM: http://www.kingoslo.com/instruments/ When viewed on my iPhone 3G, the arrow simply doesn't move back and forth smoothly enough.
This javascript works by changing the source of the arrow img-element (which is semi transparant {4 color png} floating on top the static picture of the scale {16 color png}, by the way).
I've been made aware of new image editing features in HTML5, and wondered if any of those, or any other methods will be more responsive. Also, I am getting an iPhone 4 for xmas, so that may be a bit faster, but I've got the feeling that it still will fall short for the current build, especially when I add the constant ajax updating that is required to keep the instruments change values as the driver drives along.
Thank you for your time. Any help is greatly appreciated.
Kind regards,
Marius
I think using canvas will result in much faster animation - it was created to handle drawing, whilst manipulating DOM elements is comparably expensive.
Mobile Safari is compatible with canvas.
Alternatively, you could try incorporating all the angles as one large CSS sprite, and then just manipulating its background-position CSS property (element.style.backgroundPosition in the JavaScript DOM API).
See here: http://code.google.com/p/ie7-js/
Does anyone have any experience or remarks about this javascript? Is it worth including? Do you recommend it?
I know many people, myself included that are using various IE hacks to get transparent PNG support. THis looks like a little bit more help, and as long as it works, and the size is fairly small, I wouldn't see much against using it.
I've used it before, and my results are mixed. Those scripts cause IE to churn for a bit on page load. Basically, you have to think of it as iterating through Elements and stylesheet rules to apply "fixes" for areas that are deficient in that particular rendering engine. In some cases, depending on how complicated your markup or stylesheets are, that can take a bit of time and you will see the browser hang.
That said, if you can trade off that performance cost, you will save development time as you'll spend less time hacking around IE6 quirks; IE7/IE8 will provide enough missing functionality that you can avoid certain edge cases, can develop using standards better (min-width/min-height, multiple className selectors, etc.), and certain rendering issues will disappear.
However, if you just need 24-bit transparent PNG support, use a tool built for that. Including IE7/IE8.js for PNG support alone is like pounding in a nail with a tank. Use DD_belatedPNG for that.
It works, but its worth keeping in mind that ie7.js and ie8.js do much more than provide transparent PNG support. Even with the transparent PNG support, its worth keeping in mind that transparent background images cannot be tiled (repeated) using background-repeat or positioned using background-position. This hinders any ability to use CSS rollovers using background-position. I've only used it on one site I've done, and now that I'm updating the site I can't remove the ie8.js because if I do the entire website breaks layout in IE. I don't believe I'll be using it in the future, and instead rely on simple CSS hacks or simply allow my sites to "degrade gracefully" in IE6.
I know that there are some tools for fixing the transparent PNG problem which are more flexible than this. For instance, the jQuery plugin ifixpng2 will support background position, which ie7-js doesn't do.
As long as you are aware of exactly what it fixes, I would say go for it. I'm not sure about this lib exactly, but some libs get very expensive if you have a large DOM, as they tend to hook in HTC file base behaviors on EVERY DOM Element. This causes the dreaded "Loading x of y" status bar message to flash constantly on the initial load, and any newly generated DOM content.
well its beautiful and works grate way u can use cs3 features like li:hover. we did lost of project last time using ie8.js and it works great way.
Are there ways to remove the sliding and fading effects from Firefox as an end user when I visit web pages that use such javascript effects?
When some element is inserted into the DOM, the elements after it are slided down. This is a graphical effect, that is very time and bandwith consuming when someone is viewing over a remote connection (terminal server, citrix, remote X, nx) It would just be OK to see the page in it's new shape without the sliding and many intermediate states.
Maybe there is a setting for this already (about:config)?
There are greasemonkey scripts for most popular sites to streamline the interface and eliminate such annoyances. There is no way to disable it in general because it is not a single feature but an emergent result of a combination of otherwise benign features.
To clarify that last bit... Each individual javascript function used for these animations (that is, timers and element size/placement manipulation) has legitimate uses. It is only the combination of them that is a problem, and they can be combined with other operations in myriad ways. Some sort of heuristic could possibly identify likely-annoying animations in websites at large, but individual fixes targeting specific sites (or site frameworks, all jquery sites use the same animation code, etc) will be far more effective and efficient.
I'd look into the NoScript extension for firefox- it will disable all javascript on every site, and can then be turned on for a site-by-site basis.
https://addons.mozilla.org/en-US/firefox/addon/722
Try this extension:
Disable Transitions and Animations
Today when you open a menu it often "slide" for 0.2 second or links
change color by a slow fading... Those effect are made with CSS3
animations/transition and can be heavy or reduce the website
accessibility. With this extension transition are instantaneous.