CSS-背景附件 | background-attachment
如果指定了background-image，那么background-attachment决定背景是在视口中固定的还是随包含它的区块滚动的。 /* Keyword values */ background-attachment: scroll; background-attachment: fixed; background-attachment: local; /* Global values */ background-attachment: inherit; background-attachment: initial; background-attachment: unset; 初始值 scroll 适用元素 all elements. It also applies to ::first-letter and ::first-line. 是否是继承属性 no 适用媒体 visual 计算值 as specified Animation type discrete 正规顺序 the unique non-ambiguous order defined by the formal grammar 语法 background-attachment属性被指定为下面列表中的一个关键字值。 值 fixed——此关键字表示背景相对于视口固定。即使一个元素拥有滚动机制，背景也不会随着元素的内容滚动。 local——此关键字表示背景相对于元素的内容固定。如果一个元素拥有滚动机制，背景将会随着元素的内容滚动， 并且背景的绘制区域和定位区域是相对于可滚动的区域而不是包含他们的边框。 scroll——此关键字表示背景相对于元素本身固定， 而不是随着它的内容滚动（对元素边框是有效的）。 正式语法 <attachment>#where <attachment> = scroll | fixed | local 示例 简单例子 HTML <p> There were doors all round the hall, but they were all locked; and when Alice had been all the way down one side and up the other, trying every door, she walked sadly down the middle, wondering how she was ever to get out again. </p> CSS p { background-image: url("https://mdn.mozillademos.org/files/12057/starsolid.gif"); background-attachment: fixed; } 结果 多背景图支持 此属性支持多张背景图片。你可以用逗号分隔来为每一张背景图片指定不同的<attachment>。每一张背景图片顺序对应相应的attachment 类型。 HTML <p> There were doors all round the hall, but they were all locked; and when Alice had been all the way down one side and up the other, trying every door, she walked sadly down the middle, wondering how she was ever to get out again. Suddenly she came upon a little three-legged table, all made of solid glass; there was nothing on it except a tiny golden key, and Alice's first thought was that it might belong to one of the doors of the hall; but, alas! either the locks were too large, or the key was too small, but at any rate it would not open any of them. However, on the second time round, she came upon a low curtain she had not noticed before, and behind it was a little door about fifteen inches high: she tried the little golden key in the lock, and to her great delight it fitted! </p> CSS p { background-image: url("https://mdn.mozillademos.org/files/12057/starsolid.gif"), url("https://mdn.mozillademos.org/files/12059/startransparent.gif"); background-attachment: fixed, scroll; background-repeat: no-repeat, repeat-y; } 结果 规范 Specification Status Comment CSS Backgrounds and Borders Module Level 3The definition of 'background-attachment' in that specification. Candidate Recommendation The shorthand property has been extended to support multiple backgrounds and the local value. CSS Level 2 (Revision 1)The definition of 'background-attachment' in that specification. Recommendation No significant change. CSS Level 1The definition of 'background-attachment' in that specification. Recommendation No significant change. 浏览器兼容性 Feature Chrome Edge Firefox Internet Explorer Opera Safari Basic Support 1.0 12 1.0 4 3.5 1.0 Multiple backgrounds 1.0 12 3.6 9.0 10.5 1.3 local 1.0 12 25 9.0 10.5 5.0 Feature Android Chrome for Android Edge mobile Firefox for Android IE mobile Opera Android iOS Safari Basic Support (Yes) (Yes) (Yes) 1.0 (Yes) 10.0 3.2 Multiple backgrounds (Yes) (Yes) (Yes) (Yes) (Yes) 10.0 3.2 local ? (Yes) (Yes) 25 (Yes) ? ?
