This time I will bring you the differences in the use of css3 middleweight units. What are the precautions when using css3 middleweight units. The following is a practical case, let’s take a look.
px: absolute unit, the page is displayed in precise pixels
em: relative unit, the reference point is the size of the font of the parent node, if it is defined font-size press Calculate it by yourself (the default font of the browser is 16px), 1em is not a fixed value in the entire page.
rem: Relative unit, which can be understood as "root em", calculated relative to the font size of the root node HTML. CSS3 has a new attribute and is supported by chrome/firefox/IE9+.
(In addition, please note that Chrome forces the minimum font size to be size 12. Even if it is set to 10px, it will eventually be displayed as 12px. When the font-size of the HTML is set to 10px, the calculation of the sub-node rem is still based on 12px. As a benchmark, many articles on the Internet mentioned that setting the font-size of html to 10 to facilitate calculation is not so advisable).
For mobile application of rem, please refer to Taobao pagehttp://m.taobao.com (html font-size passed Dynamic calculation acquisition)
Page benchmark 320px (20px), calculation of html font-size value:
var ele=document.getElementsByTagName("html")[0], size=document.body.clientWidth/320*20; ele.style.fontSize=size+"px"
Note: The meta scaling ratio needs to be set to 1:1
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=no" />
vw: viewpoint width, window width, 1vw is equal to 1% of the window width.
vh: viewpoint height, window height, 1vh is equal to 1% of the window height.
vmin: The smaller of vw and vh.
vmax: The larger of vw and vh.
vw, vh, vmin, vmax: IE9+ partial support, chrome/firefox/safari/opera support, iOS safari 8+ support, Androidbrowser4.4+ support, chrome for android39 support
Other units include:
%: percentage
in: inch
cm: centimeter
mm: millimeter
pt:point, about 1/72 inch
pc:pica, about 6pt, 1/6 inch
ex: Take the x height of the font of the current effect, in If the x height cannot be determined, it is calculated as 0.5em (not supported by IE11 and below, firefox/chrome/safari/opera/ios safari/android browser4.4+, etc. all require attributes and prefixes)
ch: Based on the "0" character in the font used by the node, if it cannot be found, it is 0.5em (supported by ie10+, chrome31+, safair7.1+, opera26+, iOS safari 7.1+, Android browser4.4+)
I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!
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How to use zoom attribute or overflow:auto in CSS
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