is and where selectors: secret weapons to improve front-end programming efficiency

is and where selectors: secret weapons to improve front-end programming efficiency

In front-end development, selectors are a very important tool. They are used to select elements in the document to manipulate and style them. As front-end technology continues to develop, selectors are also constantly evolving. Among them, the is and where selectors have become the secret weapon to improve the efficiency of front-end programming.

is selector is a new feature in CSS Selectors Level 4. It allows us to select elements in a more concise way. Traditional selectors use multiple class names or tag names to select, while the is selector separates multiple selectors with commas, and logical operators are used within parentheses to perform conditional judgments.

For example, if we want to select all elements with class "button" or "link", we can use the traditional selector method:

.button, .link {
  /* 样式设置 */
}

And use the is selector to simplify the code:

:is(.button, .link) {
  /* 样式设置 */
}

In this way, we can merge related selectors together to make the code more concise and readable.

In addition to the is selector, the where selector is also a new feature in CSS Selectors Level 4. The where selector is similar to the is selector and can also select elements through conditional judgment. The difference is that where selectors can apply conditions to a group of selectors, judging them as a whole.

For example, if we want to select elements with class "error" that are also "input" or "textarea", we can use the traditional selector method:

.error.input, .error.textarea {
  /* 样式设置 */
}

and use the where selector, The code can be simplified:

:where(.error) :is(.input, .textarea) {
  /* 样式设置 */
}

In this way, we can combine related selectors more intuitively and improve the readability and maintainability of the code.

The introduction of is and where selectors not only provides a more concise and readable way of writing code, but also allows us to better organize and manage selectors. By merging related selectors, we can reduce code redundancy and improve code reusability. At the same time, the logical operators of the selector also provide more powerful selection capabilities, allowing us to select more precise elements through conditional judgment.

To summarize, the is and where selectors are a secret weapon to improve the efficiency of front-end programming. Not only do they simplify how you write selectors, they also make your code more readable and maintainable. By merging the use of related selectors and logical operators, we can select elements more flexibly, reduce code redundancy, and achieve higher code reusability. In actual development, we can make full use of these two selectors to improve our programming efficiency.

I hope this article can help readers better understand and apply the is and where selectors, and improve the efficiency and quality of front-end development.

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