0 or 0px in CSS: Unit Specificity for Zero Values

In CSS, it is common to encounter the use of both "property: 0" and "property: 0px" notations for assigning zero values to properties. While both notations are valid, there is a subtle distinction to consider.

Unit Identifiers for Zero Values

According to the CSS2.1 specification, unit identifiers for length values are optional after a zero length. This means that both "0" and "0px" are acceptable implementations of zero lengths in CSS. However, it is important to note that spec does not explicitly specify any performance difference between the two.

Preference and Styles

Ultimately, the choice between "0" and "0px" is a matter of preference and coding style. Some developers find "0px" to be more visually appealing and consistent, while others consider "0" to be more concise.

Recommendation

Although it is technically acceptable to use either notation for zero lengths, it is generally recommended to use "0px" for consistency and to avoid potential confusion. This aligns with the widely accepted convention of explicitly specifying units for non-zero lengths.

In conclusion, both "property: 0" and "property: 0px" are valid options for assigning zero values in CSS. The choice between the two is influenced by individual preference and coding styles, but using "0px" is generally recommended for clarity and consistency.