Bootstrap 4.0.0 fail W3C validation? - css

I'm encountering a problem with an application I'm making, which try to Minificate my whole .css files.
It seems that bootstrap is failing W3C validation, on both normal and .min version.
Any clues about this problem?

Bootstrap's documentation explains the issue. They are using some "hacks" as workarounds for bugs of certain browsers, and also new CSS features that may not have support in validators yet.
Apart from these, the rest of their CSS is valid.
In order to provide the best possible experience to old and buggy
browsers, Bootstrap uses CSS browser hacks in several places to target
special CSS to certain browser versions in order to work around bugs
in the browsers themselves. These hacks understandably cause CSS
validators to complain that they are invalid. In a couple places, we
also use bleeding-edge CSS features that aren’t yet fully
standardized, but these are used purely for progressive enhancement.
These validation warnings don’t matter in practice since the non-hacky
portion of our CSS does fully validate and the hacky portions don’t
interfere with the proper functioning of the non-hacky portion, hence
why we deliberately ignore these particular warnings.

Related

Is there any reset Library for CSS for just Modern Browsers?

I am aiming to support just IE10+, and the newest versions of the most popular browsers. I am wondering if there is a css reset just for those specific browsers ignoring old IE and Moz fixes.
I couldn't find any, but perhaps I have overlooked some when I was searching on Google. I plan to create my own of course, I just don't want to redo work if there is a library out there I can utilize.
Thanks!
Modern as in HTML5 resets?
Blue Print Framework has a nice reset
http://html5reset.org/
Then there is YUI, http://code.google.com/p/reset5/...
A CSS base and reset is meant to apply to all HTML elements you use, so that the browser never has to reach into its default styles to render anything on your page. A few elements have been removed* in HTML5, so you could remove these from your reset if any are present, but that might be over-optimizing. For what it's worth, the YUI 3 CSS base and reset account well for modern browsers.
EDIT:
Correction: They have been marked obsolete; compliant browsers such as IE10 still need to support them, so unless you are sure your page/application will never use any of them, they should not be removed from your base/reset.
Normalize is worth a look as an alternative to a CSS reset. Instead of resetting all styles, it targets the ones that need to change to change to give you sane, consistent results across browsers in a smaller file size.
This means that there is not so many styles to clutter your dev tools debugging. It also fixes some common bugs. It's a mainstream project, that's well maintained, focuses on modern (ie8+) browsers and is used by some high profile sites.
Read more about it here.

Cross browser css rules: Mozila,chrome,safari and css2 vs css3

I have two issues I have ignored so far, but I will really appreciate some light shed onto them.
First: how can I solve differences between Safari, Chrome and Firefox and the various tags that their engines render differently? Should I just write down the right attribute for each in the same css rule? Is there no better way?
Is there a way to separate the CSS sheets for these browsers as I am doing for IE? Is this recommended?
Second: What about CSS3 attributes? Should I just write them again in the same rule after the CSS2 attributes?
Will this cause problems validating the CSS with WC3?
Welcome :)
If you start without the prefixes, you should write the code, generally, with all the semantically appropriate tags, first.
Then, you can decide what your goals are.
If you want W3C compliant CSS files, then you'd need to strip out the vendor specific prefixes by default. This would then allow the latest browsers to pick up the standardised CSS properties if they support them.
This will target less of your market than you might wish, so then you should ask if progressive enhancement is a possibility. If you can reasonably enhance the visuals by using css applied after the page has loaded, such as applying styles with jQuery, MooTools or Prototype libraries AND these libraries are already serving a purpose in your website, then you could apply additional styles with those libraries (and possibly use them in conjunction with Modernizr to determine which elements you may want to additionally support.
However, it's likely that a browser will skip a property it doesn't understand and will render the ones that it does, so I'd suggest that if you code it to W3C Standards first and then add in your additional vendor prefixes 'before' the final (correct) one, then you'll likely have satisfied reasonable measures to be compliant and meet design needs.
Edit:
There is a little bit of confusion between validation results from:
http://validator.w3.org/
and writing valid code related to vendor prefixes to get CSS effects cross-browser:
List of CSS vendor prefixes?
for working on some cross-browser CSS, you might find http://csspie.com, for IE compatibility with some CSS3 properties, useful along with http://www.colorzilla.com/gradient-editor/ for cross-browser gradients and http://cssplease.com for code that gives you alternative vendor prefixes, including different versions of IE support for many different properties.
In terms of validation, here's what W3C says about it: (see comments here: W3 VALID cross browser css gradient,) and official docs here: http://www.w3.org/TR/css3-syntax/#vendor-specific
If you code according to the specifications first and test your code out against that and then add in your vendor prefixes to get the same effects on the browsers you want to support (see progressive enhancement: What is Progressive Enhancement?) then you can be more confident that your code is supporting the appropriate standards, adding value to those with more advanced browsers and still useful for those without additional features (see also WAI III compliance, 508 compliance and others if you want to write a more inclusive site).
Caveat: Web Apps may not always be inclusive or follow these guidelines depending on who the audience is.
If you are using jquery on the site you may want to look into PrefixFree. It's a script that adds the vendor prefixes for you, so for example your put border-radius:6px; in yor css and it reads the browser and adds the appropriate vendor prefix for you via js. I like it cause it keeps my css docs more readable.

What is actually harmful in to use css hacks instead of IE conditional stylesheets?

What is harmful in to use css hacks instead of IE conditional stylesheets. What is bad with css hack , will i get any problem in css management now or in future with hacks. I read many articles but haven't found any good reason.
adding extra external conditional stylesheet means one more HTTP request.
Relying on a CSS hack means two things could possibly happen:
A patch or update could fix the hack you're relying on, breaking your site until you find out about it
Future browsers could also have buggy reactions to the hack, making your stylesheets unstable - you would need to remove the hack to fix for the newer browser and find a new workaround for the old one. Again, your site would be broken until you find out about the problem.
Either way, the safest thing to do is use standards-compliant stylesheets and conditional comments. By definition, support for these will only get better with time, so you are essentially future-proofing your site.
If you're especially concerned about the overhead of an extra stylesheet for certain browsers, consider putting them inline. Your overrides should typically be minimal - 90+% of styles should be shared across all platforms.
Biggest reason: Hacks usually rely on some implementation flaw - but if MS fixes the flaw, your hack won't work (or at least not the way you intended.)
If you use proper conditional comments, it will weather the updates fairly predictably.
This is why there was such a furor over IE7 and IE8 - both fixed a lot of bugs and jacked up a lot of sites that relied on IE6 bugs.

Making website compatible across most browsers

I am trying to figure out the most efficient way to ensure cross-browser compatibility. I have done a bit of research and learned a few interesting things such as the fact that Mozilla/Firefox can't handle a class that has a name starting with a number. Is there a way to make a CSS work for any browser or is it better to just develop multiple CSS and add code to choose which to use based on the browser being used?
You might consider using a CSS Framework such as Blueprint. It includes a CSS reset that should help.
Also, you might want to look at Yahoo's CSS reset
An aside to clarify a point:
... I have done a bit of research and learned a few interesting things such as the fact that Mozilla/Firefox can't handle a class that has a name starting with a number....
Sorry, but that's not a Mozilla limitation, it's in the CSS spec: class names must not start with a number. Any browser that allows them to isn't enforcing the rules properly.
Answered here on StackOverFlow. The relevant part of the spec is at http://www.w3.org/TR/CSS21/syndata.html#characters (see the 2nd paragraph).
To answer your question: There is no way to make a page using just one universal css and have it displayed equally in all browsers, unless you only use an extremely small sub-set of all available css (selectors, values, etc.).
The way I work is:
Use a css reset
Develop for a browser that adheres to the standards pretty well (Firefox, Chrome, Safari, Opera)
Patch things up for IE using conditional comments (because you'll probably need things that don't validate)
A good starting point would be to use CSS reset such as: http://developer.yahoo.com/yui/reset/
Your goal should be CSS that works on all browsers. If you start out with a CSS file per browser, where do you stop? Mobile Safari? Flock? Konqueror? Every version of every supported browser?
Eventually, you might need to compromise, but you can cross that road when you get there.
Regardless of your infrastructure/framework/etc you should test your code on all major browsers. If possible avoid using style sheets for browser specific problems. Browsers will change and adapt which means you might get stuck having to update a bunch of websites when new browsers come out.
CSS is a fickle beast and I haven't found any solution that covers all the quirks except for a lot of due-diligence and testing.
You might use a framework that does this for you, such as GWT, but keep in mind that you will still have some issues.

Are good CSS design and IE6 / IE7 support mutually exclusive?

Like every web developer, I usually curse the creators of IE6 with foul and untimely deaths at least once a week. Yet my company requires me to keep supporting that most-hated of browsers.
My problem today has been wanting to first use a wildcard in my CSS and then trying to use the "inherit" property instead. Neither of which are supported by IE7-.
I really, REALLY want to have good, well-structured, properly-inheriting CSS (object-oriented CSS, if you like that buzzword) but I have that sinking feeling in the pit of my stomach that sooner or later, it's going to have to be custom-purpose and location-based classes.
This poses the question: given how utterly awful IE is at handling many CSS concepts, is it impossible to adequately support this browser at the same time as having a well-structured CSS document?
Just to clarify: I'm aware that there are plenty of ways (some legitimate, some less so) to get around the bugs and shortcomings found in IE6 and 7. What I'm really asking is "if you want to have a single, well-written stylesheet that inherits correctly, must you choose between that and having a consistent look across all browsers?". Hope that makes sense.
In other words, should I stick to my principles and code a good style sheet or should I accept that IE6 still enjoys a horribly high (20% on last count) market share and bring myself to support it? Or is there some happy medium that allows me to minimise the frankenstein surgery on my HTML and CSS while still achieving some respectable results in IE?
To be fair, you can't blame it all on IE (though Microsoft certainly is by far the worst transgressor). Part of the problem with such large & rapidly-evolving standards is that it's too much of a moving target to be perfectly implemented in a timely fashion. Unfortunately, the release cycles of web browsers do not coincide with the release of new web specifications. So all browser developers can do is try to implement as many features as they can from the latest W3C recommendations, selecting what they think will be the most commonly used features to implement first.
However, things are clearly improving, and it is possible to support IE6/7 and still use proper CSS design. It's just... difficult. Take a look at this comparison of layout engines & CSS support. If you look at the overall trend, you'll see that most browsers (even IE) do tend to comply with established standards in the long-run, it just takes some browsers longer than others to implement a standard after its introduction.
And sometimes it's not that one browser is "less" standards-compliant than another. With new standards the problem is often that different development teams chose to adopt different parts of the new specification. So even though CSS3 is already beginning to be implemented by most browsers, we'll probably have to wait until CSS4 is published before seeing consistent support across all major rendering engines. And if you try to use the latest CSS3 features right now, you'll have a hard time establishing compatibility across all major browsers. But if you're using features introduced in CSS1, it's no problem at all.
Therefore, the only option--aside from using ugly CSS hacks--is to stick with well-established older specifications. Then the problem is no longer trying to conform to web standards while supporting a particular browser. Instead the problem simply becomes trying to resist the urge to use the latest & greatest CSS features.
Aside from that, the only permanent solution I see to this recurring situation is for the W3C to prioritize different parts of newly introduced specifications so that the new features can be implemented in discrete phases synchronized across all the major browsers. So, for instance, grammar rules might be given the highest priority along with a set deadline for its implementation. After that would come the second phase, which could be element & attribute selectors, and so on and so forth.
This would require a tremendous level of cooperation between the W3C and development teams, but it would be worth it. After all, it does users and web developers no good for IE to implement one subset of features from CSS3 while Firefox implements a different subset and the Webkit browsers yet another subset. A "standard" is no good until it's actually standardized across all the major rendering platforms. It's better for each browser to support fewer new features but have them all be the same features, than for them to separately introduce a ton of their own features that aren't universally supported.
Not at all - you can compensate for IE's shortcomings with conditional comments and an IE specific stylesheet, while serving your 'nice' stylesheet to other browsers.
Something else which I find helps is to use a CSS reset. While this isn't going to resolve all of IE's issues, it does give you a good baseline to work from.
The most anoying IE6 feature is it's box model handling. You should stick to margin instead when positioning boxes, and try to use relative font sizes to allow font resizing on IE. The rest of the quirks are well documented.
Using conditional comments is the cleanest way of having both a clean style sheet for well behaving browsers, and still using being beautiful on IE. This is what I use, only needing 1 css file of a few lines to repair my sites look and feel.
The dark path of crossbrowser consistent look & feel are css hacks, but I strongly discourage it's use, specialy now that for some time we'll have to target three different IE (6, 7 & 8)
Normally, if you get the style to work in both FF and Chrome/Safari, IE is only a few corrections away of being correct.
There is a great site Position Is Everything that details how FF, IE and Safari conform to standard CSS. At the site you will find most of the workarounds / cures for IE that will alleviate the need for you to write so much conditional code for your CSS.
You'll also want to check out A List Apart for more on CSS and IE. There are also great articles on tableless layout with CSS, handling the height bug in IE, etc. Good luck - IE 6 really sucks when it comes CSS.
Certainly not. If you ensure that they render the page in "standards" mode as opposed to "quirks" mode many of the common IE CSS issues are resolved. To do this you must provide a valid doctype statement at the top of the page, such as
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
As others have pointed out, another good idea is to start off your stylesheet with a snippet that removes all paddings and margins like so:
*,html {
margin: 0;
padding: 0;
}
Finally, one common problem with CSS based layouts in IE is that clearing of floats doesn't happen when you'd expect. This is to do with a hidden object property in IE called "hasLayout"; only objects that "have layout" will correctly wrap around and enclose floated child objects. It is easy to ensure that your containers "have layout" simply by specifying at least one dimension for them:
height: 1%;
width: 100%;
zoom: 1;
I do not personally use conditional IE stylesheets except for one single thing: to replace PNG backgrounds with GIFs in IE < 7 - there is nothing wrong with using them, I just find it unnescessarily complicates things when you have to define the appearance of the same object in two different places. With the three tips above and a bit of patience you should be able to create CSS based layouts using a single stylesheet that render just as well in IE 6/7 as they do in Mozilla/Webkit.
Happy coding!
IE 6 really does limit what we can do.
It’s the lack of support for advanced selectors (and inherit — IE 7 doesn’t support that either) that gets me. Just having the child selector and attribute selectors would be nice, that’d really cut down the amount of code we have to write and maintain. You can only work around the lack of support for them by duplicating your styles, so you just end up having to code as if they didn’t exist.
Sigh.
Only follow online CSS tutorials that is rendered correctly with IE6 and Chrome (or Webkit). If it looks right in both, it likely looks right in (almost) all browsers.

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