As I'm sure you all know, Internet Explorer can handle simple gradients. Here is a snippet from Twitter Bootstrap, for example:
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#e6e6e6', GradientType=0);
However, I've seen some people use two CSS rules (one for IE < 8 and one for IE 8), like so:
filter:progid:DXImageTransform.Microsoft.gradient(GradientType=0, startColorstr='#7fbf4d', endColorstr='#63a62f'); /* For Internet Explorer 5.5 - 7 */
-ms-filter: "progid:DXImageTransform.Microsoft.gradient(GradientType=0, startColorstr='#7fbf4d', endColorstr='#63a62f')"; /* For Internet Explorer 8 */
My question is, is the second rule really necessary? Twitter Bootstrap is quite thorough, yet it doesn't use any "-ms-filter" rules. According to this page, the -ms-filter attribute is an extension to CSS, and can be used as a synonym for filter in IE8 Standards mode.
My suggestion:
Use CSS3Pie -- http://css3pie.com/
This is a JavaScript library for IE6, IE7 and IE8 that patches in support for several CSS3 features, including gradients.
Yes, you can use the horrible IE-specific filter styles if you want, but CSS3Pie allows you to use standard CSS styles for these features. Much easier.
To actually answer your direct question:
Yes, the -ms-filter style is usually required. IE8 will always us it instead of filter, which is used primarily for IE6 and IE7. In some cases filter will work in IE8, but not all, so it's best to use -ms-filter to ensure IE8 compatibility.
[EDITED]
Why did they change it? Because when they released IE8, Microsoft made a big point of trying to be "standards compliant".
For a browser to be standard-compliant, it should use a vendor prefix for any CSS property it supports that is not a finalized W3C standard. So by adding the -ms- prefix, Microsoft were trying to (belatedly) undo their pollution of the global CSS namespace.
In addition, the quotes were added, because the old filter syntax without the quotes was invalid CSS (mainly because of the colon after progid), and caused issues with some browsers. (I had an instance some time ago with Firefox 3.6 where it was dropping all styles following a filter style that rotated an element - took ages to work out what was happening).
The fact that Microsoft retained backward compatibility with the original filter syntax, was largely a matter of pragmatism. MS couldn't afford to break all the sites using the old syntax. But there was a strong implication from Microsoft that developers should use both because they would drop support for the old filter style in subsequent versions of IE. As it turned out, they dropped support for both filter and -ms-filer in one fell swoop, but the implications given at the release of IE8 were sufficient for it to become recommended practice to provide both syntaxes in your stylesheet.
At the time when IE8 was released, XHTML was the new flavor of the month, and writing code that validated perfectly was top of the list for a lot of developers. This was probably a strong driving force in the change of syntax to include the quotes. Because of the stray colons, it is impossible to write CSS that validates using the old filter style. Using the new -ms-filter styles instead allowed people to write valid CSS. As good ideas go, this one didn't really work out because of course people had to keep using the old syntax anyway, but the intent was good.
It's worth pointing out that other proprietary styles were given the same treatment. For example, you can use -ms-behavior in IE8 instead of the old behavior style. No-one uses it. Why? I don't really know.
Another fact worth knowing is that the W3C are in the process of standardizing a CSS property called filter. It will do a completely different job to the Microsoft filter style, and work completely differently. If/when it is standardized and browsers start supporting it, there will be an explicit clash between the two syntaxes.
Seems like you answered your own question. Yes they're needed. Microsoft trying to get more in line with the standards means that some versions of IE have their own slightly different syntax rules for the filter property.
In IE7 just filter: followed by the progid:DXIma... etc will work. But for IE8+ there is the IE7 fallback it may use in compatibility mode, and the more proper -ms- prefixed property for filter, denoting a vendor specific css property, and its value inside qoutes.
What harm would it do to leave it in?
If the browser doesn't understand the line of CSS it will just ignore it.
Those two lines of CSS are almost identical. I would hazard a guess that Microsoft decided to change the syntax for proprietary CSS from IE8 onwards utilising the - (hyphen) prefix which other browsers have been using for yonks.
Technically the CSS isn't W3C compliant either way, so another line of proprietary CSS can do no harm.
It's not worth trying to understand IE at the best of times!
Related
I've got this SCSS code:
.gradient-text {
color: mix(#cea427, #fbe758); // Fallback to average of 2 colors
background: -webkit-linear-gradient(0deg, #cea427, #fbe758);
-webkit-background-clip: text;
-webkit-text-fill-color: transparent;
}
Fiddle
At first I just wanted to make this code work in webkit-based browsers and then add different approach for firefox, but I've found out that at least latest nightly firefox runs this code too, even if it's vendor-prefixed for webkit.
I won't worry if there was only one property, which can be either supported by firefox or not. But having 2 properties makes me nervous about the situation where only one of them is working. For example, supported -webkit-linear-gradient and unsupported -webkit-background-clip will work vastly different from my expectations. So, is there any way I can check browser support for multiple CSS rules and gracefylly switch to fallback if at least one of them is missing?
And also, is there any list of foreign vendor prefixes support (like -webkit- prefix support in FF)?
In these sort of situations, I always find it very helpful to check MDN. In this case, you can check the articles for linear-gradient, background-clip and -webkit-text-fill-color. Near the bottom, there is always a section titled Browser compatibility. It lists, in a table, browsers that support the CSS rules and in footnotes goes into specifics. For example, about the -webkit-text-fill-color, it says that
[1] This feature is implemented behind the preference layout.css.prefixes.webkit, defaulting to false. Since Gecko 49 (Firefox 49.0 / Thunderbird 49.0 / SeaMonkey 2.46) the preference defaults to true.
This should answer your question on why the -webkit- prefixed version is supported, and since when. Also note that at the top, the article mentions
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
So: ye be warned.
In this particular case, you might be able to get away with what you want to do, at least in Firefox and Chrome. Other browsers... that's trickier.
Your other question is if you can gracefully switch to a fallback when a rule is not supported. Unfortunately, this is not possible in pure CSS. It is possible to write rules that specifically target Chrome or Firefox though, but I would advise against using those. You could maybe check for support using JavaScript, but that is something I wholeheartedly advise against.
Finally, "is there any list of foreign vendor prefixes support (like -webkit- prefix support in FF)?" Sort of. Again, MDN is usually very complete and up-to-date. Hope that helps.
I have a website which I support as far as IE8, no further.
When I first launched the site, I decided to use CSS vendor prefixes for CSSs elements such as border-radius, box-shadow etc. I did this from a complete noob standpoint.
However, is a better approach not to use them and simply let browsers catch up rather than patch up for the sake of uniformity?
No, you shouldn't remove all of them, however you may as well remove the ones which are no longer required.
How can I find out which prefixes are no longer required?
Can I use... is a great resource for checking browser support for various CSS, HTML and JavaScript features. If you perform a search for box-sizing, for instance, it will tell you that all modern browsers have partial support for this and that Firefox requires the -moz- prefix. You can also view all of the CSS support tables on just one page here.
How can I clarify that the prefixes are no longer required?
There are a couple of online resources which display information about browser usage. An example of this is StatCounter. StatCounter offers browser version statistics which can be filtered on time. If we look at the last 3 months, we can guestimate that we should still aim to support Firefox 20+, Chrome 25+, IE 8+ and Safari 5.1+.
Personally, I would just keep your vendor prefixes for now - this still remains professional practice - those browsers who don't need them, will simply ignore them anyway.
Our approach is to drop those which aren't needed.
border-radius
box-shadow
box-sizing (soon? firefox still uses it. Noted by #James Donnelly)
opacity (not a prefix, but no need for the ms-filter thingie)
inline-block (same here, no need for inline+zoom fix)
If you really want to get rid of prefixes, one of the solutions you can try is -prefix-free. It's a javascript plugin which loops through your stylesheets and, according to current browser removes the unused ones.
Although I didn't test it, I think it will definetely lower the performance.
You can also remove prefixes for properties which doesn't have a signifact meaning for functionality and/or user experience, like border-radius, box-shadow etc. You would have to test each element how it behaves without these properties. E.g. you have a button with border-radius: 4px. In a browser which doesn't support border-radius it will simply have rough corners. You must only consider if its worth sacrificing.
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.
I have been learning about IE's rather ridiculous-looking requirements for shadows, gradients, etc., and I'm running into some contradictions on this point:
Many sites suggest the following lines are necessary for a gradient/shadow combination:
filter: progid:DXImageTransform.Microsoft.gradient(startColorStr='#FFFFFF', EndColorStr='#F8F8F8') progid:DXImageTransform.Microsoft.Shadow(Strength=2, Direction=170, Color='#C6C6C6');
-ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorStr='#FFFFFF', EndColorStr='#F8F8F8') progid:DXImageTransform.Microsoft.Shadow(Strength=2, Direction=170, Color='#C6C6C6')"; }
CSS3Please.com suggests only the first filter is necessary for full compliance with IE 5.5-9, i.e. that the -ms-filter is of no use at all. Is -ms-filter needed any more or was that a temporary case in IE's development?
To answer your question even though I don't agree with its use, no it is not required. The "-ms-" prefix and other prefixes (such as "-moz-" and "-webkit-") are browser-specific and are usually just used while browsers are developing new properties. They leave the prefixed properties in later versions of the browser so that webpages using the prefixed property will still work, but both ways do the exact same thing.
P.S. IE 9 does support CSS3. It was released with Windows 7 SP1.
As of right now I believe only Firefox support -moz-border-radius property. I am surprised that twitter uses it.
Are any other browsers planning on supporting this or does CSS3 have something like this in the works?
Edit: I also found -webkit-border-top-left-radius and then the CSS3 version
So when is CSS3 coming out?
CSS3 has border-radius.
For now, Mozilla- and WebKit-based browsers have experimental support, -moz-border-radius and -webkit-border-radius. It's not bad to use them now, as long as you understand they are temporary measures until they are properly implemented. I would expect it's not too long before you see full support for border-radius in Mozilla, Firefox and IE. (Well, hopefully IE.)
Update: as of August 2016, with border-radius being natively available in all native desktop browsers (and most mobile browsers, not to mention), the stringency of using -moz-border-radius, -webkit-border-radius and similar is being slowly relaxed.
Because the CSS3 spec hasn't been finalised, Mozilla and Webkit decided to implement their own method of rounded corners, doing it in the correct way, by adding the vendor-specific tag at the front.
This is done so that when the CSS3 is FINALLY released, should they change how border-radius is supposed to work (eg: the order of the parameters), then none of the sites using the vendor-specific methods will be broken. Mozilla and WebKit can just go ahead and implement the W3C style and developers can slowly move over to that.
It's not too surprising that you're seeing some websites using it, especially for something like rounded corners where it's not going to make a massive difference to the user experience. And I mean, it's just IE users who are missing out, and they deserve everything they get.
It bugs me when people talk about CSS3 coming out. It's not a complete spec like the previous ones. It has been broken up into separate modules that may increment their versions independently.
So Selectors Level 4 may make Recommendation before CSS Backgrounds and Borders Level 3 does.
So, will CSS3 arrive? Eventually, but not all a once. So don't wait for it, start using it now (where applicable).
CSS3 has something like this in the works.
According to this, IE 8 will not support border-radius.
Any CSS property that starts with a dash (e.g. -moz, -webkit) is a browser-specific property.
This allows browser vendors to experiment with new CSS properties. Doing so is a common part of the process for writing new CSS specs, to allow web developers to see how the properties work and raise issues.
Hence you’ll find a lot of CSS 3 properties, like border-radius currently implemented in some browsers with vendor-specific extensions.
There’s nothing particularly wrong with using these on production sites, as long as you’re aware they’ll only work in the one browser.
CSS 3 should be out any decade now :)
Browser-based properties are only meant for interim fixes for that particular browser, and are supposed to be deprecated when either the W3C adopts them into CSS, or not. I wouldn't rely on them to be cross-browser or even be kept for the particular browser.