Is the Universal Selector (*) Really a Performance Killer in Modern Browsers?

The Universal Selector's Performance Implications

In optimizing website performance, the universal selector (*) has often been a target of scrutiny. This article delves into its true performance impact, addressing questions about its efficiency compared to specific element selectors.

Universality vs. Specificity

The universal selector applies styles to all elements, while element selectors target specific elements. Conventional wisdom held that the universal selector was slower due to its wide applicability, requiring more processing.

Modern Browser Optimization

However, modern browsers have greatly improved their performance in handling the universal selector. Tests conducted with millions of page views reveal negligible impact on performance, as long as computationally intensive effects (e.g., box shadows, 3D transformations) are not applied broadly.

Efficiency Comparison

Contrast the following style rules:

* { margin: 0; padding: 0; }

body, h1, p { margin: 0; padding: 0; }

While the universal selector appears more concise, it is essentially equivalent to the element selector approach in terms of efficiency. Both rules apply styles to the same elements and have minimal impact on performance in modern browsers.

Exceptions and Considerations

While the universal selector performs efficiently in most cases, there are exceptions:

• Avoid using the universal selector to override styles with other rules later in the document.
• Limit applying computationally expensive effects to every element using the universal selector.

Conclusion

The myth that the universal selector is inherently slow is unfounded in modern browsers. When used appropriately, it offers a concise and efficient way to apply styles to all elements. If performance is a primary concern, however, it is advisable to avoid using it with computationally intensive effects.

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