翻译自stackoverflow.com,源地址:http://stackoverflow.com/questions/6747242/what-is-the-difference-between-max-device-width-and-max-width-for-mobile-web
有同学需要开发web页在iphone/android手机上访问,想问max-device-width 与 max-width 有什么区别,他打算针对不同的屏幕大小加载不同的样式,就像下面这样:
@media all and (max-device-width: 400px)@media all and (max-width: 400px)
这两者有什么不同?
max-width 指的是显示区域的宽度,比如浏览器的显示区域宽度
(max-width is the width of the target display area, e.g. the browser)
max-device-width 指的是设备整个渲染(显示)区域的宽度,比如设备的实际屏幕大小,也就是设备分辨率
(max-device-width is the width of the device’s entire rendering area, i.e. the actual device screen)
max-height
与 max-device-height
也是同理
更进一步说,max-width在窗口大小改变或横竖屏转换时会发生变化
max-device-width只与设备相关,横竖屏转换或改变尺寸,缩放都不会发生变化(部分android的宽高会互换而IOS不会)
如何你需要调整浏览器大小查看页面的变化,那开发过程中就使用 max-width,尽管在实际的生产环境中用max-device-width更精确
要是只关心两者的区别,到这已经足够了,下面是关于两者在实际应用的区别,来自另一篇文章:
http://www.javascriptkit.com/dhtmltutors/cssmediaqueries2.shtml
在CSS的媒体查询中,width与device-width之间的区别总是让人感到迷惑,下面就让我们来阐述一下两者的区别。
device- width指的是设备本身的宽度,也就是屏幕的分辨率,比如说你手机的分辨率是1440*900,这表示你的屏幕宽是1440px, 所以device-width是1440px。大部分的手机宽度不到480px,(当然今后的趋势是越来越大)。iphone 4的device-width就只有320px,即便对外宣称有640*960.这要归功于iphone的retina显示方式,也就是用两个像素来表示屏幕上一个CSS像素,IPAD3也是这样的。官方说IPAD3跟前几代一样采用的device-width是768px,它的实际分辨率达到了1536*2048,就是这个原因。
尽管device-width在指定特定的设备更有用,相比之下width在创建响应式页面时用途更加广泛。下面的表格是一个例子,
CSS Media DimensionsDeviceresolution (px)device-width/ device-height (px)iPhone320 x 480320 x 480, in both portrait and landscape modeiPhone 4640 x 960320 x 480, in both portrait and landscape mode.device-pixel-ratio
is 2iPhone 5, 5s640 x 1136320 x 568, in both portrait and landscape mode. device-pixel-ratio
is 2iPhone 6750 x 1334375 x 667, in both portrait and landscape mode. device-pixel-ratio
is 2iPhone 6 plus1242 x 2208414 x 736, in both portrait and landscape mode. device-pixel-ratio
is 3iPad 1 and 2768 x 1024768 x 1024, in both portrait and landscape modeiPad 31536 x 2048768 x 1024, in both portrait and landscape modeCSS pixel density is 2Samsung Galaxy S I and II480 x 800320 x 533, in portrait modeCSS pixel density is 1.5Samsung Galaxy S III720 x 1280360? x 640?, in portrait modeHTC Evo 3D540 x 960360 x 640, portrait modeCSS pixel density is 1.5Amazon Kindle Fire1024 x 6001024 x 600, landscape mode( 也可以参考:CSS3 媒体查询移动设备尺寸 Media Queries for Standard Devices)
需要注意的是,在苹果设备上,device-width指的总是设备处于肖像模式时的宽,不会随设备横竖屏转换变化,就是说不管怎么换,宽都是不会变的,高也一样。
下面是一个通过媒体查询区别设备和不同尺寸的例子:
/* #### Mobile Phones Portrait #### */@media screen and (max-device-width: 480px) and (orientation: portrait){/* some CSS here */}/* #### Mobile Phones Landscape #### */@media screen and (max-device-width: 640px) and (orientation: landscape){/* some CSS here */}/* #### Mobile Phones Portrait or Landscape #### */@media screen and (max-device-width: 640px){/* some CSS here */}/* #### iPhone 4+ Portrait or Landscape #### */@media screen and (min-device-width: 320px) and (-webkit-min-device-pixel-ratio: 2){/* some CSS here */}/* #### iPhone 5 Portrait or Landscape #### */@media (device-height: 568px) and (device-width: 320px) and (-webkit-min-device-pixel-ratio: 2){/* some CSS here */}/* #### iPhone 6 and 6 plus Portrait or Landscape #### */@media (min-device-height: 667px) and (min-device-width: 375px) and (-webkit-min-device-pixel-ratio: 3){/* some CSS here */}/* #### Tablets Portrait or Landscape #### */@media screen and (min-device-width: 768px) and (max-device-width: 1024px){/* some CSS here */}/* #### Desktops #### */@media screen and (min-width: 1024px){/* some CSS here */}
通过以上方式,我们的CSS媒体查询方案已经很完善了,但为了页面展示跟我们想像的一样,还要增加一个viewport标签: meta
tag.
了解更多请参考:CSS:媒体查询 CSS3 Media Queries
本文转自:CSS3: 移动端开发中 max-device-width 与 max-width 的区别