[Bole Online Note]: ① May 6, Google Developer Center launched a Web development best practices manual. Bole online resource channel after excerpts of the resources, has invited friends to participate focused on Web development manual translation. ② Since Air Max 2012 Black Red White the translator has been working almost all friends, all in his spare time to participate, Air Max 2012 Green Orange Black each translation schedule will be different (Please understand), so manual Chinese version will not be released in accordance with the order of the English version of the chapter. ③ manual Chinese version is not yet complete, please do not reprint, thank you. [REVIEW]: By default, CSS will be used as the rendering of obstructive resources, which means that the browser has been handled well, even if some of the content of the page, as long as CSSOM not built well, Air Jordan Outlet it will not be rendered. So give your CSS weight, increase the transmission speed, and the use of media types and media queries to unblock. 626969-030 Air Jordan 4 Retro Fear Pack Nike Kids Sneakers In the previous section we saw the critical need to have a way of rendering DOM (Document Object Mode, Document Object Model) and CSSOM (CSS Object Model, CSS Object Model) to construct the render tree, which is a very important in rendering performance Meaning: HTML and CSS rendering process are obstructive resources. New Nike Tr Fit Shoes Black Navy HTML is 2015 Nike Free 5.0 obvious, because there is no DOM, we have nothing to render, but the requirements for CSS may not be obvious. If we try to render an ordinary page, without letting CSS blocking the rendering process, what would happen? By default, the focus of learning is seen as a CSS rendering resources obstructive media types and media queries let us bring some CSS resources marked as non-blocking rendering resources regardless of obstructive or nonobstructive behavior, all the CSS resources examples are downloaded through the browser has CSS in the New York Times Web site of the New York Times website without CSS above shows the NYTimes look at use and do not use CSS, which shows why CSS is available only until rendering - lack of CSS page it is impossible to use. In fact, the right of the user experience is often called 'Flash of Unstyled Content' (FOUC). So the result is that the browser will also have the DOM and CSSOM when rendering interface. CSS is an obstructive rendering SALOMON resources, the need to make it as fast as possible to download to the client, and at first when rendering optimization. However, if some of the CSS styles can be used only under certain conditions how to do it? For example, when the page is printed, or when projected to the big screen. If these resources are not blocked rendered, then it would be great! CSS 'media type' and 'media inquiries' so that we can deal with the following conditions: \u0026 lt; link href = \u0026 quot; style.css \u0026 quot; rel = \u0026 quot; stylesheet \u0026 quot; \u0026 gt; \u0026 lt; link href = \u0026 quot; print.css \u0026 quot; rel = \u0026 quot ; stylesheet \u0026 quot; media = \u0026 quot; print \u0026 quot; \u0026 gt; \u0026 lt; link href = \u0026 quot; other.css \u0026 quot; rel = \u0026 quot; stylesheet \u0026 quot; media = \u0026 quot; (min-width: 40em) '\u0026 gt; a media query consists of a media type and expression 0 or more check the conditions of the special characteristics of the media constituted, for example, our first style statement did not use any media New Nike Tr Fit Shoes Black Red type and query, so it applies to all kinds of situations - that is, it will always be blocking rendering on the other hand, the second style is used only when the content is printed. - Maybe you want to reset the layout or change the font, etc. - so that when Authentic Black Gold Nike KD 7 Mens Basketball Shoes the pattern is first loaded, it does not block the page . rendering last style declaration provides a medium by the browser to execute the Womens Nike Kobe VIII query: If conditions are met, then the browser will download finished and after treatment are rendered using media queries in the style, our appearance 616175-700 Black/Metallic Pine Green-Glow Dark Armory Slate Nike LeBron 11 Outlet can be customized to specific use cases, such as display and print, as New Nike Tr Fit Running Shoes Black well as some dynamic conditions, such as a change of direction on the screen, adjust the size and so on. When you declare your style resource, be sure to carefully pay attention to media types and media inquiries, because they ! have a great impact on the performance of key rendering path Let us consider some practical examples: \u0026 lt; link href = \u0026 quot; style.css \u0026 quot; rel = \u0026 quot; stylesheet \u0026 quot; \u0026 gt; \u0026 lt; link href = \u0026 quot; style.css \u0026 quot; rel Nike Air Max = \u0026 quot; stylesheet \u0026 quot; media = \u0026 quot; screen \u0026 quot; \u0026 gt; \u0026 lt; link href = \u0026 quot; portrait.css \u0026 quot; rel = \u0026 quot; stylesheet \u0026 quot; media = \u0026 quot; orientation: portrait \u0026 quot; \u0026 New Nike Free 5.0 V4 Shoes Black Red gt; \u0026 lt; link href = \u0026 quot; print. css \u0026 quot; rel = \u0026 quot; stylesheet \u0026 Nike Air Max 2011 quot; media = 'print \u0026 quot; \u0026 gt; The first statement is blocking rendering, and match all circumstances. The second statement also blocked rendered: 'screen' is the default type, if you do not specify any type, the default will be set to 'screen'. Therefore, the first and the second is actually the same. Article declare a dynamic media inquiries, when the page is being loaded will be judged. When the page is loaded with the orientation of the device, according to decide whether portrait.css will block rendering. The last statement is only used when the page is being printed, so when the page is first loaded into the browser, it does not block rendering. Finally, remember that 'blocking rendering' only with whether the resources are blocked in the first browser page rendering related. Whether blocking, CSS resources will still be downloaded through the browser, but as a non-blocking low priority resources.Google Web Development Best Practices Manual (4.1.3): obstruction rendering CSS