How to use selector to get equal and unequal elements in css

In web development, Cascading Style Sheets (Cascading Style Sheets, CSS for short) is a language used to control the layout and appearance of web pages. CSS has many powerful features, one of which is the selector. Selectors are used to locate HTML elements to which styles should be applied, such as setting fonts, colors, backgrounds, etc.

In CSS selectors, there are many different symbols and keywords that can be used to define different selection methods. In addition to the common class selectors and ID selectors, the equal and not equal operators can also be used to select specific elements.

Equal operator

The equal operator (=) is a special symbol in the selector, which can be used to select only those elements whose attribute value is equal to the specified value. For example, the following selector will select all button elements with a class attribute value of "button":

button[class="button"] {
  /CSS代码 /
}

Such a selector will only be applied to button elements with a class attribute value of "button", not other elements. This selection method is useful for special-case styling, such as controlling styling through the use of custom properties.

Not equal to operator

The opposite of the equal to operator, the not equal to operator (!=) selects all elements whose attribute values ​​are not equal to the specified value. For example, the following selector will select all elements whose class attribute value is not equal to "button":

*[class!="button"] {
 / CSS代码 /
}

Such a selector will not select elements whose class attribute value is "button", but will select all other elements. . This selection method is useful when you need to exclude certain elements from some elements.

Selector Combination

In addition to using the equality or inequality operators alone, they can also be combined with other selectors to select the target element more precisely.

For example, the following selector will select all button elements whose class attribute value contains "button" but does not end with "disabled":

button[class*="button"]:not([class$="disabled"]) {
 / CSS代码 /
}

This selector includes equal and not equal operations characters, as well as wildcard selectors and pseudo-class selectors. It will only select button elements whose class attribute value contains "button", but not button elements whose class attribute value ends with "disabled". This gives us a very powerful way to combine selectors, allowing us to select the elements we need more accurately.

Conclusion

In CSS, selectors are a very useful tool that can help us control the layout and appearance of web pages. The equality and inequality operators are two important selector symbols that can help us select specific elements more accurately. Selector combination takes us a step further and can achieve more precise selection by combining different selectors. Mastering these selectors can greatly improve our CSS skills and make our web pages look more beautiful and professional.

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