What is the use of !important in css? The role of !important in css

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The role of !important in CSS

Add {*rule !important} to support IE6.0, IE7. 0 and FireFox write hack

* can be recognized by IE series browsers, but not by Firefox browser;

! important can only be recognized by IE7.0 and Firefox, but IE6.0 cannot be successfully applied

DIFFERENCE

(1)The hack that distinguishes IE and Firefox is: border:2px solid # f00;*border:1px solid #f00;

(2) The hack to distinguish Ie6.0 from Ie7.0 and firefox is: border:1px solid #f00!important;border:2px solid #f00;

Analysis

In (1), the reason why * is placed after After the border is set for the second time, the latter attribute covers the previous attribute, so it is a one-pixel border.

In (2), the reason why !important is placed in the first border setting is because it increases the priority of this border, even if it is used later or even in Setting the border N times is also invalid, but Ie6.0 does not accept this rule, causing it to apply the second border setting, that is, the second time overwrites the first principle. It is not that it does not recognize it! important; so its border is a 2-pixel red box.

Example

CSS

 #Box {
      color:red !important;
      color:blue;
 }

HTML

 <p id="Box"> 在不同的浏览器下，这行字的色应该不同！</p>

This example should be the usage of important that you often see. In IE environment, this line of text is blue, in firefox Below, it is red

Related recommendations:

Detailed introduction on how to use !important statement to force priority in CSS

Usage of !important in CSS and its performance under IE6_html/css_WEB-ITnose

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