What's the Difference Between Double Colon (::) and Single Colon (:) in ::before and :after in CSS?
In CSS, ::before and :before, ::after and :after are pseudo-elements used to add content to selected elements.
The ::before and ::after pseudo-elements were introduced in CSS3 and are the recommended approach. The double colon :: is used to distinguish pseudo-elements from pseudo-classes. Pseudo-elements are used to add content to specific parts of an element. For example, ::first-line, ::first-letter, ::before, ::after, etc.
The single colon : was used in CSS1 and CSS2 and is still supported in CSS3 for backward compatibility. The single colon : is used to denote pseudo-classes, such as :hover, :active, :focus, etc.
For instance, if your styles need to be compatible with older browsers, you might need to use :before and :after. In modern browsers, it is recommended to use ::before and ::after.
Summary:
- Double colon
::is used for pseudo-elements in CSS3. - Single colon
:is used for pseudo-elements in CSS2 and all pseudo-classes, while maintaining backward compatibility.
Currently, many browsers support the double colon, but if you need to maintain compatibility with older browsers during development, it is still recommended to use the single colon.