I want to start using modular CSS, but I'm having trouble figuring out the best way to implement it. I was thinking I could just use a bridging technique, where I have one in my HTML and then #import statements for each module. While I like the simplicity of that method, I'm concerned about the negative effects it has on performance, since the #import-ed stylesheets will download later and not necessarily in parallel. So I want to know if there are any other popular techniques for implementing modular CSS. I don't really want to do multiple tags because PageSpeed and Yslow complain about so many stylesheets (although I know it is actually more efficient than #import). Ideally I would like to combine the stylesheets into one on the server, so the browser only every requests one stylesheet.
Using server side includes to assemble your "modules" into one style sheet on the server side is definitely recommended here. So is having some sort of cache on the server so it doesn't have to do the assembly on every request. There are lots of technologies available for this but your message doesn't include anything about your software stack.
Check out the Compass CSS Framework. It supports modular CSS through mixins and makes CSS a lot more pleasant to work with in general by adding variables, arithmetic, and including style frameworks such as Blueprint.
Just be extremely careful how you do this. Caching is your friend, and if you opt to deliver purpose-delivered, server-side generated CSS pages, you'll lose the benefit of caching. It's the classic chicken and egg problem. Do you preload and cache all your CSS and take the hit up front, or custom load each page and incur a hit on every page change? Only you know what's best.
Don't go too overboard on this. I've worked in huge shops where a minor minification change resulted in a 5 gig/day improvement (with millions of uniques)...but most sites I've worked on wouldn't see much if any gain at all. If you've got time on your hands, go nuts. Otherwise, proportion your response based on the need. Those optimizers report on ideal conditions, and we all know that isn't the case in real life. Try runnig the optimizer on some major sites sometime (don't miss trying to validate them either) Makes for good web-geek fun.
Related
I'm testing a website speed using PageSpeed Insights tool.
In the result page, one of the warnings suggested me to reduce byte size of css, html and js files.
At the first I tried to remove comments, but nothing changed.
How can I do that?
Should I remove spaces and tabs?
It seems to be a very long operation, worth it?
The action of removing spaces, tabs and useless chars is called minify.
You don't need to do that, there are a lot of services that can minimize files for you.
for example:
http://www.willpeavy.com/minifier/
Be care if you have jquery code: sometimes it removes spaces in wrong place.
You have two things to do to reduce page size:
Minify CSS & JS files
In server side, if you are running your website via Apache, you can install APC, for page cahing. You'll have better parformances
APC
In addition to CSS minifier/prettifier tools above, I recommend using proCSSor for optimizing CSS files. It offers variety of advanced options.
Never found those tools to be much use beyond giving some tips for what might be slowing it down. Minifying is unlikely to achieve much. If you want to speed up your site, save the page and see what the largest files are. Generally they will be the image files rather than the code, and see if you can reduce these.
Also, try and test it on two servers - is your host slow?
If your html file is massive, that suggests a problem with the site's structure - it is rare that a page needs to be large.
Finally, large javascript files are most likely to be things like jquery. If Google hosts these, then use the hosted version. That way, it will probably be already in a user's cache and not impact on your loading time.
EDIT, after further testing and incorporating the issues discussed in the comments below:
PageSpeed Insights is an utterly amateurish tool, and there are much more effective ways to speed up the rendering time than minifying the codes.
PageSpeed Insights is an utterly amateurish tool, that as a matter of standard advises to reduce HTML, CSS and JS file sizes, if not minified. A much, much better tool is Pingdom Website Speed Test. That compares rendering speed to the average of the sites it is asked to test, and gives the download times of the site's components.
Just test www.gezondezorg.org on both, and see the enormous difference in test results. At which the Google tool is dead wrong. It advises to reduce the CSS and JS files, while its own figures (click the respective headers) show that doing so will reduce their sizes with 3.8 and 7.9 kB, respectively. That comes down to less than 1 millisecond download time difference! (1 millisecond = 1/1000 of a second; presumed broadband internet).
Also, it says that I did do a good thing: enable caching. That is BS as well, because my .htaccess file tells browsers to check for newly updated files at every visit, and refresh cached files whenever updated. Tests confirm that all browsers heed that command.
Furthermore, that site is not intended to be viewed on mobile phones. There is just way too much text on it for that. Nevertheless, PageSpeed Insights opens default with the results of testing against mobile-phone criteria.
More effective ways to speed up the rendering
So, minifying hardly does anything to speed up the rendering time. What does do that is the following:
Put your CSS codes and Javascripts as much as possible in one file each. That saves browser-to-server (BTS) requests. (Do keep in mind that quite a number of Javascripts need the DOM to be fully loaded first, so in practice it comes down to putting the scripts as much as possible in 2 files: a pre- and a post-body file.)
Optimize large images for the web. Photoshop and the likes even have a special function for that, reducing the file size while keeping the quality good enough for use on the web.
In case of images that serve as full-size background for containers: use image sprites. That saves BTS requests as well.
Code the HTML and JS files so that there is no rendering dependency on files from external domains, such as from Twitter, Facebook, Google Analytics, advertisement agencies, etc.
Make sure to get a web-host that will respond swiftly, has a sufficient processing capacity, and has a(n almost) 100% up-time.
Use vanilla/native JS as much as possible. Use jQuery or other libraries only for tasks that would otherwise be too difficult or too time-consuming. jQuery not only is an extra file to download, it is also processed slower than native JS.
Lastly, you should realize that:
having the server minify the codes on the fly generally results in a much slower response from the server;
minifying a code makes it unreadable;
de-minifying tools are notorious for their poor performance.
Minifying resources refers to eliminating unnecessary bytes, such as extra spaces, line breaks, and indentation. Compacting HTML, CSS, and JavaScript can speed up downloading, parsing, and execution time. In addition, for CSS and JavaScript, it is possible to further reduce the file size by renaming variable names as long as the HTML is updated appropriately to ensure the selectors continue working.
You can find plenty of online tools for this purpose, a few of them are below.
HTML Minify
CSS Minify
JS Minify
good luck!
What is the point of these CSS Frameworks? I don't understand them. When I look at them, all I see is boring layouts that seem overbearingly-difficult to adapt to your own unique designs.
Is this the case, or am I just missing something here? I'm referring to (frameworks in general) things like Blueprint, Less, Skeleton, 960 Grid system, Base, Gridless, etc etc etc.
I know this is a really simple thing but I just don't get it. I have searched but have not found anything that helps me to understand what the big deal is. When I look at their code, all I see is mess. Weird class and id names all over the place.
(This isn't a rant or complaint by the way, I just really don't get it.)
CSS frameworks are pre-prepared software frameworks that are meant to
allow for easier, more standards-compliant web design using the
Cascading Style Sheets language. Most of these frameworks contain at
least a grid. More functional frameworks also come with more features
and additional JavaScript based functions, but mostly design
orientated and unobtrusive. This differentiates these from functional
and full JavaScript frameworks. -Wikipedia
Advantages
They can help you learn CSS. You might just literally not know how to pull off a solid multi-column layout. A framework may be a
good place to get your feet wet understanding how CSS works.
They provide code that you just don't need to write from scratch every time, like resets. I've long been a proponent that the star
selector (*) margin/padding reset is a fine reset. I use it all the
time. But... if you are starting a major new project that is going
to be loads of pages, live for years and years, and will grow over
time, you should invest right away in a more robust reset. All
these frameworks start with brilliant resets that cover all the
bases and will have you covered for years to come.
They relieve cross-browser concerns. You can't undervalue this. We've all felt the burn of finding out our sites are borked
in some browser or another at a hugely inopportune time. Frameworks
are built to bring their magic to all browsers.
It helps you build good habits. Like including a print stylesheet in your projects. I always intend to build one, and I
often do, but the chances are a lot higher that I do it if I have
one there from the get-go.
They encourage grid based design. Which is a good thing. Grids don't mean boring! They just help you achieve better
readability, scanability, balance visual weight, flexibity,
expandability, and just overall page page cohesiveness.
They come with documentation. If you need help getting started, framework generally come with some support files. This can be
particularly nice if you are designing a site you will be handing
off to a client. You can just let them know what framework you used
and refer them to that documentation for support requests.
They lay groundwork. If you are using something like YUI, your life will be a lot easier if you use All-YUI-Stuff-All-The-Time.
It's built to work together and built for expandability.
CSS-Tricks
Also see: Comparison of CSS frameworks
As part of my job I maintain/develop an internal web application. It has relatively few users and just isn't that big. I've got a global CSS file that contains some re-used styles, but 90% of my page-specific styles really really ARE page-specific; they are things like pseudo-column widths (a lot of my output is just non-tabular enough to make tables a poor choice). I have taken to just throwing a <style> block at the top of these pages.
I know this is frowned upon, but every time I read about the reasons for separate CSS files the only one that really stands out is caching. In this case that doesn't matter; it is WAY down on the list of things I would do if I needed to speed up the application. Are there any other reasons, or can I stop feeling guilty?
every time I read about the reasons for separate CSS files the only one that really stands out is caching
Really?
Every time I read about their usage, the fact that you can change something in a CSS file and all pages that include it will have the change is the most important reason to use them.
Having your CSS centralized is a good thing even if your specific pages have different specific rules. It helps you unify the basic CSS structure across the site and when looking for how a specific effect was achieved it will be easy to locate.
These are all worthy reasons to use CSS files, well above any caching/performance reasons.
I face a similar problem, in that most of my styles are very much page-specific. However, my site is far from small, so I had to find a solution.
What I ended up doing was creating a folder css/pages, and naming each CSS file the same as the page that uses it. Then, my PHP "template" can just check if(file_exists("css/pages/".basename($_SERVER['PHP_SELF']))) and add the relevant <link/> tag, resulting in minimal effort on my part.
Just because your site is small is not a valid reason to disregard efficiency, although I have to say I'm a bit of an efficiency nerd so I'll probably be more pedantic over that :p
Ultimately, there's nothing "wrong" with just putting page-specific CSS directly in the page, just make sure that anything that is used on more than one page is in a file so you don't have to repeat yourself.
In my opinion if your app only contain a few web pages(3-5 pages) then you can go ahead define it at the top of the web pages. If your app is going to grow into more that 3-5 web pages then global CSS will help with maintainability and scalability.
Makes for cleaner mark-up, quicker load. Really applies to template and dynamic development. Don't be afraid to use it. It's not like you're going over to the dark side.
With regards to mobile websites on smartphones;
Assuming that:
HTML code is rarely a huge amount of data
Compressed JS files are not so heavy
Images are often loaded via CSS (at least could always)
It's the same sequence (PHP + SQL = HTML) on server-side.
It seems way faster to do this way and quite easy to maintain.
And even if:
It's not graceful at all (hide Useless elements instead of generating a sharp and beautiful HTML code)
Useless code is loaded and treated.
Best practices for mobiles websites don't recommend to do this way.
Is it a good idea to rely only on different CSS to create a mobile version of a website? (Actually on different header templates, in order not to load useless JS)
It's probably a bad idea to serve HTML with elements that you know will be useless to your users.
Small amounts of kb make a difference on mobile download speed.
It means your CSS and Javscript need to be more complicated.
You users might see the content if the CSS or JS are slow loading.
It will take more processing power (I think CSS styles will still be applied to the hidden elements).
It's likely to be easier to manage on the server
But to answer the question "Is it a good idea to rely only on different CSS to create a mobile version of a website?";
Yes if you want your mobile users to have the same content as your large screen users. Which you probably should as this is normally what the users want.
No if you want to serve them different content.
Speaking for Belgium, I know a lot of people are still on Edge instead of 3G and loading a webpage takes some time. If we would have to load pages made your way, we would indeed be loading a lot of useless code, giving us quite a bad experience.
I'd suggest you stop being lazy and write your mobile websites the way they should be written. Think of your visitors and user experience; it honestly isn't that much of an effort.
I think you basically answered your own question already. Like BoltClock said, do what you want, but I sure wouldn't recommend doing things your way.
Why HTML/JavaScript/CSS are not becoming compiled languages (or maybe even merge into a single compiled language)? What if browsers were running "Browser Virtual Machine" and html/javascript/css sources could by compiled to a "browser bytecode". Wouldn't it help developers and users a lot?
I can see a few challenges:
What to do with zillions of existing pages? Make this compilation optional, so if you want you can use plain old html. If you want to feed a browser with a compiled page just use .chtml for example.
How search providers would index pages? Make a decompiler that would decompile bytecode into exact original sources (for example like flash can be decompiled). Or search providers can use the same virtual machine and get data they need from there.
How to make it compatible with all browsers? Have one centralized developer (lets say w3c) to develop this virtual machine and then each browser would embed it.
But what about benefits:
Speed.
Size.
No more "loose" and "half-correct" html. It is either correct or won't compile.
Looks the same in every (supported) browser.
If not a bytecode then at least have some native compression going on, html probably is not the most efficient way of data storing. I know there is gzip but why to compress pages every time on a server and decompress in a browser if we can compress it once and feed it to a browser?
So what stops us from taking this road (well, besides a huge amount of effort to make it all happen)?
Ah, but Javascript IS becoming a compiled language. Check out Firefox 3.5 with TraceMonkey. It's insanely fast compared to um you-know-who's browser. It's true that JS will never be C, but it's a much more dynamic language than C is, and in many ways that makes it more expressive and powerful.
As far as HTML goes, I don't think that the lack of validity of HTML is a huge detriment to speed. I think the engines that put together the visual representation and manipulate the DOM need to get a lot better (um, IE, I'm looking in your general direction...). CSS compliance needs to get better, and CSS itself needs to get more powerful. (Get on the bus with CSS 3 people!)
But I do think that speed is going to get better on Firefox and Chrome to such an extent that people really ARE going to start using it for mainstream application development. It's funny. Adobe seems to be selling Flash as their platform for dynamic web content, MSFT is selling Silverlight for dynamic web content, and Google just wants to really improve HTML and Javascript to display dynamic web content. And Google's doing pretty well at it so far, I must say...
Your ideas have validity when they are applied to JavaScript. As others have noted, to one degree or another several vendors are trying to apply those principles to JS even now. Another big step in this area will likely be the Chrome OS Google has announced. However, when it comes to (X)HTML and CSS I think your ideas may be missing the point.
The world wide web is not a buggy and inconsistent application platform but a massive and unprecedented collection of interconnected documents. The power of the web is in the abstraction of the data from the often rigid (and breakable) visual layouts and increasingly complex in-page functionality largely provided via JavaScript. Encoding these pages in (X)HTML is ideal for making them accessible to the widest possible audience both in terms of browsers and in terms of technical knowledge required to author a page.
More and more the web is being used as an application platform - which is a powerful and exciting use of this technology - but we cannot lose sight of the fact that these Ajax-driven "web 2.0" apps are merely documents with extended functionality. Compilation doesn't make sense for a document and compression is already happening (via gzip and the like).
On a more practical note, the W3C moves at a glacier's pace and browser vendors take turns between jumping-the-gun supporting experimental features in unfinished specs and taking their sweet time supporting other specs which have been on the table and in common usage for years. The whole processes is like herding cats. I wouldn't hold my breath for them to make the kind of radical changes you're proposing any time soon.
Since HTML and CSS aren't code they can't be compiled. Google Chrome's V8 engine does actually convert JS into byte code, expect other rendering engines to follow suit!
http://code.google.com/apis/v8/design.html
We recently reworked a php template system I've helped create to use minify to compress multiple JS and CSS into one file each, seeing our file sizes drop to about 20% of the origial combined sizes. Minify also does gzip and caching so it's really amazing for speeding up websites.
http://code.google.com/p/minify/
In short you can't compile non-code, which HTML and CSS are. JS can be compiled and is starting to be, but all depends on what browsers feel like doing.
Browsers just need to be on the ball regarding supporting web standards. The more browsers do this, the less headache us web developers have. I was quite happy with YouTube's very public drop of support for IE6. We need more action like that for the web to move forward.
The V8 javascript engine (also embedded in Google Chrome, but it's open-source and liberally licensed so you're welcome to use it in the next browser you write!) does compile Javascript to native machine code -- of course, it does it "just in time" (like most modern compilers -- Java, C#, etc!), not "ahead of time" (like Fortran did in 1954 when computers were just too weak to handle compilation in the midst of execution). I'd be surprised if other good JS engines, like those in the very latest Firefox and Safari, didn't do the same.
Looks like you're not advocating "javascript as a compiled language" (since it obviously already IS compiled, if you're using a good JS engine), but rather "ahead-of-time" compilation for it (just when most modern languages are essentially abandoning ahead-of-time compilation). Pushing machine code rather than compilable code down the wire sounds like a mostly horrible idea -- much larger size, difficulties in supporting one CPU vs another, security nightmares in properly sandboxing it, etc, etc) with not much in term of compensating benefits.
That said, if you're really keen on pushing machine code to the client, try out nativeclient (as long as the client is an x86 machine - forget every smart phone on the planet, many netbooks, good old macs, etc) -- at least it promises a fix to the security nightmares. If and when you're happy with nativeclient, transforming a just-in-time compiler into an ahead-of-time one is a far easier technical challenge (if you want to keep using Javascript for the sources rather than other languages, of course).
See here for a previous discussion on the matter
Not all of the reasons given are necessarily valid, but one important one is that, unless you're Google, server-side CPU cycles are a lot more valuable than client-side cycles: so it's easier to have the client compile/optimize what is quite often dynamically generated HTML/JavaScript, rather than the server.
Ken
Speed.
You're assuming that it takes significant time to parse HTML. However it might be that that time is insignificant compared to the time required for something else, e.g. the time required to layout the text on the end-user's window.
No more "loose" and "half-correct" html. It is either correct or won't compile.
You already get that, using [X]HTML.
Looks the same in every (supported) browser.
You seem to be saying that there should only be one browser, or that all browsers would support it equally.
Internet standards don't happen by having a single body (the w3c) implementing something and declaring it a standard. Instead, internet standards happen by having multiple independent bodies creating multiple implementations. A consequence is:
Some people have developed something that isn't standard yet (i.e. they're ahead of the standard)
Some people haven't yet developed something that is standard (i.e. they're behind of the standard)
I think your idea is sound, however there's still no way to enforce a standard. Thus if there was a non-supported feature, there's a good chance the entire page would simply not display anything. In the current setup, critical information can still be passed.
Google V8, which is one of many new-generation javascript engines 'compiles' javascript into pseudocode, much like .NET 'compiles' c# on the fly. Nothing magical here. Expect more of it esp. as webapps get heavier and more demanding
HTML
HTML is pretty much XML. DTD'd exist for various versions and developers can check against that at any time.
CSS
CSS is not a programming language, however I do agree that "compiled" CSS could work seeing as compilation would compress it. However with the support that CSS has and with the number of essential hacks any CSS needs to have, you'd never manage to compile it without errors.
JS
As others have mentioned, JS IS becoming a compiled language except the browser compiles it for you and not you yourself.