Does the CSS Star Selector Secretly Slow Down Your Website?

The Hidden Pitfalls of the CSS Star Selector

While CSS offers a wide range of selectors for styling elements, the star selector (*), which targets all elements, has raised concerns about its potential negative impact on performance. To fully understand the implications of using the star selector, it's crucial to delve deeper into its effects.

Performance Considerations

As noted by Steve Souders, a renowned expert in CSS optimization, the star selector can indeed affect page rendering performance. When a browser encounters a star selector, it must iterate through every element in the page, matching the selector pattern. This exhaustive process can slow down page load times, especially if the star selector is used excessively.

Specific Case Example

To illustrate the performance penalty, consider the following CSS rule:

* {
  margin: 0;
  padding: 0;
}

While this code seems straightforward, it's more expensive for the browser to apply than a more specific selector. Because the browser applies selectors right to left, it begins by checking all elements that match the key selector, which in this case is *. Consequently, it attempts to match all elements on the page against this pattern.

Alternative Approaches

To mitigate the performance impact, it's recommended to use more targeted selectors whenever possible. By selecting only the specific elements that need to be styled, the browser can apply the styles more efficiently. For example, instead of using *, consider using class or ID selectors to target specific elements or groups of elements.

In conclusion, while the star selector can be a convenient way to reset CSS properties, its overuse can result in degraded performance. By opting for more precise selectors, developers can optimize their CSS code for faster page rendering.

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