探究css !important的应用之道

时间:2022-11-20 15:42:10

定义及语法:

!important是CSS1就定义的语法,作用是提高指定样式规则的应用优先权

语法格式:{ cssRule !important },即将!important写在定义的最后面,

例如:

box{color:red !important;}

兼容性:

探究css !important的应用之道

应用场景:

场景一:

<!--应用场景一-->

<div id="content">
<p class="p1">The daimler executive familiar with the collaboration said daimler and byd might display a prototype of the jointly developed car as early as the paris auto show in october.
熟悉合作情况的戴姆勒高管说,戴姆勒和比亚迪最早有可能于10月份在巴黎车展上展出这款合作开发汽车的样车。</p> <p class="p2">The daimler executive familiar with the collaboration said daimler and byd might display a prototype of the jointly developed car as early as the paris auto show in october.
熟悉合作情况的戴姆勒高管说,戴姆勒和比亚迪最早有可能于10月份在巴黎车展上展出这款合作开发汽车的样车。</p>
</div>
    #content p{
color: orange;
}
.p1{color: blue;}
.p2{color:blue !important;}

显示效果:

探究css !important的应用之道

注:

默认情况下,class的优先级小于id,所以,p1中即使用class重定义了自身样式,也无法生效,所以继承父级属性,这行字还是orange!
但是,p2中,用了important提升优先级(或看成强制重定义),所以这里的css得以生效,这行字变为了蓝色!

 

场景二:

<!--场景二-->
<div class="color1 color2">
The daimler executive familiar with the collaboration said daimler and byd might display a prototype of the jointly developed car as early as the paris auto show in october.
熟悉合作情况的戴姆勒高管说,戴姆勒和比亚迪最早有可能于10月份在巴黎车展上展出这款合作开发汽车的样车。
</div>
	/*应用场景二*/

	.color1{color: blue;}
.color2{color:orange !important;}

显示效果:

探究css !important的应用之道

注:

当出现多个class共同控制某个样式时,可以根据需求,在某个class里面通过!important来
优先显示

在线演示:http://codepen.io/anon/pen/OVjXPQ