The difference between the <acronym> and <abbr> tags lies in their intended usage and the way they are rendered.
The <acronym> tag is used to define an acronym, which is an abbreviation formed from the initial letters or parts of a phrase. It is intended to provide a full explanation or expansion of the acronym to aid understanding. The <acronym> tag is not widely supported in HTML, and its usage is discouraged. Instead, it is recommended to use the <abbr> tag for both acronyms and abbreviations.
On the other hand, the <abbr> tag is used to define an abbreviation. It can represent a shortened form of a word, phrase, or name. The <abbr> tag does not provide a full explanation or expansion like the <acronym> tag. It is typically used to mark up abbreviations for stylistic or semantic purposes. By default, browsers may render the abbreviated text with a dotted underline and show the full form of the abbreviation as a tooltip when hovered over.
In summary, the <acronym> tag is specifically for defining acronyms and providing their full explanations, but it is not widely supported. The <abbr> tag is more versatile and is used for defining both acronyms and general abbreviations, without necessarily providing full explanations. It is the recommended choice for marking up abbreviations in HTML.
Here’s an example of how the <abbr> tag can be used to mark up an abbreviation:
<p>The <abbr title="World Health Organization">WHO</abbr> is a specialized agency of the United Nations.</p>
In this example, the abbreviation “WHO” is marked up using the <abbr> tag. The title attribute is used to provide additional information or the full expansion of the abbreviation. When a user hovers over the abbreviation, they may see a tooltip displaying the full form of the abbreviation, in this case, “World Health Organization”.
It’s worth noting that the <acronym> tag is not widely supported, so it’s recommended to use the <abbr> tag instead.