Lien 26- Media types. 7.1 Introduction to media types One of the most important features of style sheets is that they specify how a document is to be presented on different media: on the screen, on paper, with a speech synthesizer, with a braille device, etc. Certain CSS properties are only designed for certain media (e.g., the 'page-break-before' property only applies to paged media). On occasion, however, style sheets for different media types may share a property, but require different values for that property.
For example, the 'font-size' property is useful both for screen and print media. The two media types are different enough to require different values for the common property; a document will typically need a larger font on a computer screen than on paper. Therefore, it is necessary to express that a style sheet, or a section of a style sheet, applies to certain media types. 7.2 Specifying media-dependent style sheets There are currently two ways to specify media dependencies for style sheets: all print. Lien 27 - Media Queries. Abstract HTML4 and CSS2 currently support media-dependent style sheets tailored for different media types. For example, a document may use sans-serif fonts when displayed on a screen and serif fonts when printed.
‘screen’ and ‘print’ are two media types that have been defined. Media queries extend the functionality of media types by allowing more precise labeling of style sheets. A media query consists of a media type and zero or more expressions that check for the conditions of particular media features. Among the media features that can be used in media queries are ‘width’, ‘height’, and ‘color’. Status of This Document This section describes the status of this document at the time of its publication. A W3C Recommendation is a mature document that has been widely reviewed and has been shown to be implementable. This document has been reviewed by W3C Members, by software developers, and by other W3C groups and interested parties, and is endorsed by the Director as a W3C Recommendation. Lien 28 - Media Queries.
Abstract HTML4 and CSS2 currently support media-dependent style sheets tailored for different media types. For example, a document may use sans-serif fonts when displayed on a screen and serif fonts when printed. ‘screen’ and ‘print’ are two media types that have been defined. Media queries extend the functionality of media types by allowing more precise labeling of style sheets. A media query consists of a media type and zero or more expressions that check for the conditions of particular media features. Status of This Document This section describes the status of this document at the time of its publication. A W3C Recommendation is a mature document that has been widely reviewed and has been shown to be implementable. This document has been reviewed by W3C Members, by software developers, and by other W3C groups and interested parties, and is endorsed by the Director as a W3C Recommendation. Please see the Working Group's implementation report and the Media Queries Test Suite. 1. 3.
Lien 30 -Using the viewport meta tag to control layout on mobile browsers. The upcoming release of Mobile Firefox (Fennec) 1.1 features improved support for the <meta name="viewport"> tag. Previous versions of Fennec supported the width, height, and initial-scale viewport properties, but had problems with some sites designed for iPhone and Android browsers. We now support the same properties Mobile Safari does, and we also changed Fennec to render mobile sites more consistently on screens of different sizes and resolutions. touch.facebook.com before: touch.facebook.com after: You can see these changes for yourself in the latest Fennec 1.1 and trunk nightly builds for Maemo, Windows, Mac, or Linux.
Background Mobile browsers like Fennec render pages in a virtual "window" (the viewport), usually wider than the screen, so they don't need to squeeze every page layout into a tiny window (which would break many non-mobile-optimized sites). Mobile Safari introduced the "viewport meta tag" to let web developers control the viewport's size and scale. Viewport basics. Lien 29 - Safari HTML Reference: Supported Meta Tags. Discussion Use the viewport meta key to improve the presentation of your web content on iOS. Typically, you use the viewport meta tag to set the width and initial scale of the viewport.
For example, if your webpage is narrower than 980 pixels, then you should set the width of the viewport to fit your web content. If you are designing a Safari on iOS-specific web application, you should set the width to the width of the device. Table 1 describes the properties supported by the viewport meta key and their default values. When providing multiple properties for the viewport meta key, you should use a comma-delimited list of assignment statements. Donot use a semicolon as a deliminator.A space may work as a deliminator but a comma is preferred.For numeric properties, if the value contains a non-numeric character but starts with a number, then the number prefix is used as the value. You do not need to set every viewport property. To set the initial scale to 1.0, add this to your HTML file: