What is the difference between classes and IDs in CSS?
In CSS, both classes and IDs are used as selectors to target specific elements and apply styles. However, there are some key differences between them in terms of usage and behavior:
- Selectivity: IDs have a higher specificity than classes. This means that when both a class and an ID selector target the same element, the styles defined by the ID selector will take precedence over the styles defined by the class selector. IDs are considered more specific and are generally used for unique elements.
- Reusability: Classes are designed for reuse and can be applied to multiple elements. You can assign the same class to multiple elements to apply the same styles. This promotes code reusability and allows you to define consistent styles across different elements.
- Uniqueness: IDs are intended to be unique within a document. According to HTML standards, each element should have a unique ID within the document. It’s important to ensure that IDs are not repeated because it can lead to invalid HTML and cause unexpected behavior.
- CSS Specificity: IDs have a higher specificity value compared to classes, which means that an ID selector has a stronger influence on the styles than a class selector. This can be useful when you want to override or apply specific styles to a particular element.
- Style Inheritance: Classes can be inherited by child elements. If a parent element has a class assigned to it, the child elements can inherit and apply the styles defined for that class. IDs, on the other hand, are not inheritable.