How to calculate css weight

Css weight calculation method: First create an HTML sample file; then pass "div#app.child[name="appName"] /a=1,b=2,c=1—> weight =1 100 10 10=121/” can be used to calculate the weight.

The operating environment of this tutorial: windows7 system, css3 version, thinkpad t480 computer.

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CSS weight is determined by four values. It is easier to explain by looking at a picture:

The picture is in English. I will translate it and explain it separately. The definitions of the four levels are as follows:

First level: inline style, such as: style="color:red; ", the weight is 1000. (This method will make the css difficult to manage, so it is not recommended)

Second class: ID selector, such as: #header, the weight is 0100.

Third level: class, pseudo-class, attribute selector such as: .bar, weight is 0010.

Fourth level: label, pseudo-element selector, such as: div::first-line weight It is 0001.

Finally, add these values ​​up, and then it is the weight of the current element.

Others:

Attributes with unconditional priority only need to use !important after the attribute. It overrides element styles defined anywhere within the page. (There are some bugs in ie6 support).

Wildcards, sub-selectors, adjacent selectors, etc. For example, *, >, , the weight is 0000. The style inherited by

has no weight.

CSS weight calculation method

Calculate the number of ID selectors in the selector (=a)

Calculate the sum of classes, attributes and Number of pseudo-class selectors (=b)

Calculate the number of tags and pseudo-element selectors in the selector (=c)

Ignore global selectors

In respectively After calculating the values ​​of a, b, and c, connect the three numbers abc in order to form a new number. The changed value is the calculated weight of the selector. If the calculated weight values ​​of two selectors are the same, the "nearest principle" is adopted.

Example:

div#app.child[name="appName"] /a=1,b=2,c=1 —>权重 = 1 + 100 + 10 +10 = 121/

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