From 33058f2b292b3a581333bdfb21b8f671898c5060 Mon Sep 17 00:00:00 2001 From: Peter Bengtsson Date: Tue, 8 Dec 2020 14:40:17 -0500 Subject: initial commit --- .../api/window/getdefaultcomputedstyle/index.html | 144 +++++++++++++++++++++ 1 file changed, 144 insertions(+) create mode 100644 files/zh-cn/web/api/window/getdefaultcomputedstyle/index.html (limited to 'files/zh-cn/web/api/window/getdefaultcomputedstyle') diff --git a/files/zh-cn/web/api/window/getdefaultcomputedstyle/index.html b/files/zh-cn/web/api/window/getdefaultcomputedstyle/index.html new file mode 100644 index 0000000000..2ec99a1b9a --- /dev/null +++ b/files/zh-cn/web/api/window/getdefaultcomputedstyle/index.html @@ -0,0 +1,144 @@ +--- +title: Window.getDefaultComputedStyle() +slug: Web/API/Window/getDefaultComputedStyle +translation_of: Web/API/window/getDefaultComputedStyle +--- +
{{APIRef("CSSOM")}}{{Non-standard_header}}
+ +

getDefaultComputedStyle() 给出元素的所有CSS属性的默认计算值(computed values )，忽略作者样式。也就是说，只考虑用户代理和用户风格。

+ +

语法及参数说明

+ +
let style = window.getDefaultComputedStyle(element[, pseudoElt]);
+
+ +
+
element
+
获取计算样式的元素
+
pseudoElt {{optional_inline}}
+
指定匹配的伪类. 通常情况下可以为空.
+
+ +

返回的样式是一个 CSSStyleDeclaration 对象.

+ +

例子

+ +
var elem1 = document.getElementById("elemId");
+var style = window.getDefaultComputedStyle(elem1);
+
+ +
<style>
+#elem-container {
+   position: absolute;
+   left:     100px;
+   top:      200px;
+   height:   100px;
+ }
+</style>
+
+<div id="elem-container">dummy</div>
+<div id="output"></div>
+
+<script>
+    var elem = document.getElementById("elem-container");
+    var theCSSprop = window.getDefaultComputedStyle(elem).position;
+    document.getElementById("output").innerHTML = theCSSprop; // 将会输出 "static"
+</script>
+ +

Description

+ +

The returned object is of the same type as the object returned by getComputedStyle, but only takes into account user-agent and user rules.

+ +

使用伪元素

+ +

getDefaultComputedStyle 同样可以从伪元素中获取属性 (比如, ::after, ::before).

+ +
<style>
+ h3:after {
+   content: ' rocks!';
+ }
+</style>
+
+<h3>generated content</h3>
+
+<script>
+  var h3       = document.querySelector('h3'),
+      result   = getDefaultComputedStyle(h3, ':after').content;
+
+  console.log('the generated content is: ', result); // 返回 'none'
+</script>
+
+ +

备注

+ +

The returned value is, in certain known cases, expressly incorrect by deliberate intent. In particular, to avoid the so called CSS History Leak security issue, browsers may expressly "lie" about the used value for a link and always return values as if a user has never visited the linked site, and/or limit the styles that can be applied using the :visited pseudo-selector. See http://blog.mozilla.com/security/2010/03/31/plugging-the-css-history-leak/ and http://hacks.mozilla.org/2010/03/privacy-related-changes-coming-to-css-vistited/ for details of the examples of how this is implemented.

+ +

Specifications

+ +

Proposed to the CSS working group.

+ +

浏览器兼容性

+ +

{{CompatibilityTable}}

+ +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + +
FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatNo}}19{{CompatNo}}{{CompatNo}}{{CompatNo}}
pseudo-element support{{CompatNo}}19{{CompatNo}}{{CompatNo}}{{CompatNo}}
+
+ +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + +
FeatureAndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatNo}}197.5{{CompatNo}}{{CompatNo}}
pseudo-element support{{CompatNo}}19{{CompatNo}}{{CompatNo}}{{CompatNo}}
+
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