gis根据属性表特定属性

gis根据属性表特定属性

Vendors—browser makers—are free to implement extensions to the CSS specifications that, in most cases, are proprietary to their browser. They may do this for a number of reasons, such as adding new features for users, or for experiments and debugging. Most often, though, the extensions are used to release and test browser features that have been developed in the preparation of W3C drafts that have not yet reached Candidate Recommendation status—the extensions allow these new properties to be widely tested before they become available as standard CSS properties.

供应商(浏览器制造商)可以自由实施CSS规范的扩展，这些扩展在大多数情况下是其浏览器专有的。 他们可能出于多种原因执行此操作，例如为用户添加新功能或进行实验和调试。 不过，大多数情况下，这些扩展用于发布和测试在准备尚未达到候选推荐标准的W3C草案中开发的浏览器功能-这些扩展允许这些新属性在成为标准属性之前得到广泛测试。 CSS属性。

In order to accommodate the release of vendor-specific extensions, the CSS specifications define a specific format that vendors should follow.

为了适应特定于供应商的扩展的发布， CSS规范定义了供应商应遵循的特定格式。

The format is quite simple: keywords and property names beginning with – (dash) or _ (underscore) are reserved for vendor-specific extensions. As such, vendors should use the following formats:

格式非常简单：以–(破折号)或_(下划线)开头的关键字和属性名称保留用于特定于供应商的扩展名。 因此，供应商应使用以下格式：

'-' + vendor specific identifier + '-' + meaningful name '_' + vendor specific identifier + '-' + meaningful name

This approach allows any vendor-specific extension to coexist with any future (or current) CSS properties without causing conflicts because, according to the W3C specifications, a CSS property name will never begin with a dash or an underscore:

这种方法允许任何特定于供应商的扩展名与任何将来(或当前)CSS属性共存，而不会引起冲突，因为根据W3C规范，CSS属性名绝不会以短划线或下划线开头：

“An initial dash or underscore is guaranteed never to be used in a property or keyword by any current or future level of CSS. Thus, typical CSS implementations may not recognize such properties, and may ignore them according to the rules for handling parsing errors. However, because the initial dash or underscore is part of the grammar, CSS2.1 implementers should always be able to use a CSS-conforming parser, whether or not they support any vendor-specific extensions.”

“保证当前或将来的任何CSS级别都不会在属性或关键字中使用开头的破折号或下划线。 因此，典型CSS实现可能无法识别此类属性，并且可能会根据处理解析错误的规则将其忽略。 但是，由于开头的短划线或下划线是语法的一部分，因此CSS2.1实现者应该始终能够使用符合CSS的解析器，无论它们是否支持任何特定于供应商的扩展。

A number of extensions are known to exist. Their prefixes are outlined in Table 1.

已知存在许多扩展。 表1概述了它们的前缀。

Table 1. Vendor Extension Prefixes PrefixOrganisation-ms-Microsoftmso-Microsoft Office-moz-Mozilla Foundation (Gecko-based browsers)-o-Opera Software-atsc-Advanced Television Standards Committee-wap-The WAP Forum-webkit-Safari (and other WebKit-based browsers)-khtml-Konqueror browser 表1.供应商扩展前缀 字首 组织 -ms- 微软 mso- 微软办公软件 -moz- Mozilla Foundation( 基于Gecko的浏览器) -o- Opera软件 -atsc- 先进电视标准委员会 -wap- WAP论坛 -webkit- Safari(和其他基于WebKit的浏览器) -khtml- Konqueror浏览器

Use these Extensions with Care! Even though vendor-specific extensions are guaranteed not to cause conflicts (unless two vendors happen to choose the same identifier, of course), it should be recognized that these extensions may also be subject to change at the vendor’s whim, as they don’t form part of the CSS specifications, even though they often mimic the proposed behavior of existing or forthcoming CSS properties.

小心使用这些扩展！ 即使保证了特定于供应商的扩展名也不会引起冲突(当然，除非有两个供应商碰巧选择了相同的标识符)，但应该认识到，这些扩展名也可能会因供应商的要求而异，因为它们不会构成CSS规范的一部分，即使它们经常模仿现有或即将出现CSS属性的拟议行为。

Although these extensions can be useful at times, it’s still recommended that you avoid using them unless it’s absolutely necessary. It’s also worth noting that, as is usually the case with proprietary code, the extensions will not pass CSS validation.

尽管这些扩展有时会很有用，但除非绝对必要，否则仍建议您避免使用它们。 值得注意的是，与专有代码通常一样，这些扩展将无法通过CSS验证。

If you must use extensions, you should use those that are closely related to equivalent CSS properties (be that CSS1, 2, or 3), so that you can switch to the standard property later on, and remove the extension when the browser implements the correct specification.

如果必须使用扩展名，则应使用与等效CSS属性(即CSS1、2或3)密切相关的扩展名，以便稍后可以切换到标准属性，并在浏览器实现正确的规格。

Bearing this in mind, let’s go back a few years and take as an example the opacity property, which is part of CSS3 (Candidate Recommendation May 2003), which few browsers actually supported (opacity was implemented in Firefox 1.0, Opera 9, and Safari 1.2). Therefore, authors resorted to using vendor-specific extensions to cater for the lack of CSS3 opacity support at the time. Gecko-based browsers (like Mozilla) used the –moz-opacity property, and Safari 1.1 used -khtml-opacity. Internet Explorer versions 5.5 and above used the non-standard filter property.

考虑到这一点，让我们回溯几年，以opacity属性为例，它是CSS3(2003年5月候选推荐)的一部分，实际上很少支持浏览器(opacity是在Firefox 1.0，Opera 9和Safari中实现的) 1.2)。 因此，作者诉诸于使用特定于供应商的扩展来解决当时缺乏CSS3不透明性支持的问题。 基于Gecko的浏览器(如Mozilla)使用–moz-opacity属性，而Safari 1.1使用-khtml-opacity。 Internet Explorer 5.5及更高版本使用了非标准的筛选器属性。

Bringing together the above extensions, the following method was (and is still) commonly used to apply opacity to a range of browsers:

综合以上扩展，下面的方法曾经(并且现在)仍然是用来将不透明度应用于各种浏览器的：

.test{ background: red; /* IE filter extension */ filter: progid:DXImageTransform.Microsoft.Alpha(opacity=60); width:100%; /* Required for IE filter */ -moz-opacity: 0.6; /* Mozilla extension */ -khtml-opacity:0.6; /* Konqueror extension (Safari 1.1)*/ opacity: 0.6; /* the correct CSS3 syntax */ }

In the code fragment above, Internet Explorer will use the filter property and ignore the other opacity declarations. Older Gecko browsers that don’t understand the CSS3 opacity property will respect the –moz-opacity property instead, and Safari 1.1 will respect the -khtml-opacity property. Finally, if it’s supported, the CSS3 opacity property will be respected by other browsers and browser versions. Of course, a browser that doesn’t support element opacity will ignore the lot.

在上面的代码片段中，Internet Explorer将使用filter属性，并忽略其他不透明度声明。 不了解CSS3 opacity属性的较旧Gecko浏览器将改为使用–moz-opacity属性，而Safari 1.1将采用-khtml-opacity属性。 最后，如果支持，其他浏览器和浏览器版本将使用CSS3 opacity属性。 当然，不支持元素不透明度的浏览器将忽略很多内容。

The Internet Explorer filter property is a proprietary Microsoft extension to CSS that clearly doesn’t follow the correct naming rules for vendor-specific extensions. On the other hand, the Mozilla and Safari (-moz-opacity and –khtml-opacity) properties do follow the rules, and although the code won’t validate, you can be sure these properties will be relatively safe from conflicts.

Internet Explorer筛选器属性是Microsoft专有CSS扩展，显然不遵循针对特定于供应商的扩展的正确命名规则。 另一方面，Mozilla和Safari(-moz-opacity和–khtml-opacity)属性确实遵循规则，尽管代码无法验证，但您可以确保这些属性相对安全，不会发生冲突。

Even though browsers such as Firefox, Opera, and Safari eventually implemented the CSS3 opacity property, the style rules like the one in the example above still continued to work, ensuring a seamless transition between the old and the new. (Note that Konqueror versions up to and including 3.5.4 do not support CSS3 opacity.)

即使诸如Firefox，Opera和Safari之类的浏览器最终实现了CSS3 opacity属性，上面示例中的样式规则仍继续起作用，从而确保了新旧之间的无缝过渡。 (请注意，Konqueror版本不低于3.5.4，不支持CSS3不透明。)

As you can see, extensions can be useful, and can provide a measure of longevity; however, it’s not advisable to rely on the availability of extensions. It’s also possible that CSS3 properties may be changed before they become the standard. Therefore, as the W3C states, “Authors should avoid vendor-specific extensions.”

如您所见，扩展名很有用，并且可以延长使用寿命。 但是，不建议依赖扩展的可用性。 CSS3属性也有可能在成为标准之前进行更改。 因此，正如W3C所述，“作者应避免使用特定于供应商的扩展。”

Due to the very nature of vendor-specific extensions, they’re not well documented for public use, so it’s difficult to provide full and accurate listings of all the available extensions. The following links may be used as a guide, but we urge you to carry out your own research if you want to use these extensions:

由于特定于供应商的扩展的性质，因此没有足够的文档供公众使用，因此很难提供所有可用扩展的完整且准确的清单。 以下链接可用作指南，但如果您要使用这些扩展名，我们敦促您进行自己的研究：

Internet Explorer CSS Attributes: Index

Internet Explorer CSS属性：索引

CSS Reference: Mozilla Extensions

CSS参考：Mozilla扩展

CSS3 Columns in Mozilla

Mozilla中CSS3列

Safari CSS Reference

Safari CSS参考

Webkit CSS Styles

Webkit CSS样式

Opera 9 CSS Support

Opera 9 CSS支持

Opera CSS Extensions

Opera CSS扩展

As we already mentioned, we don’t recommend that you use these extensions in a real application. It’s fine to use them for testing purposes, and for trying out CSS properties that haven’t been implemented yet. This will prepare and educate you for the time when the correct CSS syntax becomes available for general use.

正如我们已经提到的，我们不建议您在实际应用程序中使用这些扩展。 可以将它们用于测试目的，并尝试尚未实现CSS属性。 当正确CSS语法可用于一般用途时，这将为您做好准备并进行培训。

While an explanation of all the properties is beyond the scope of this book, we will look at a few that you might find useful, and investigate a few extensions that you might find in use elsewhere.

尽管对所有属性的解释超出了本书的范围，但我们将研究一些您可能会发现有用的内容，并研究一些您可能会在其他地方使用的扩展。

翻译自: https://www.sitepoint.com/vendor-specific-properties/

gis根据属性表特定属性

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