Which is more correct: <h1><a>...</a></h1> OR <a><h1>...</h1></a>
Are both <h1><a ...> ... </a></h1> and <a ...><h1> ... </h1></a> valid HTML, or is only one correct? If they are both correct, do they differ in meaning?
Answer
Both versions are correct. The biggest difference between them is that in the case of <h1><a>..</a></h1> only the text in the title will be clickable.
If you put the <a> around the <h1> and the css display property is block (which it is by default) the entire block (the height of the <h1> and 100% of the width of the container the <h1> resides in) will be clickable.
Historically you could not put a block element inside of an inline element, but this is no longer the case with HTML5. I would think that the <h1><a>..</a></h1> approach is more conventional though.
In the case where you want to put an anchor on the header, a better approach than <a id="my-anchor"><h1>..</h1></a> would be to use either the id or the name attribute like this: <h1 id="my-anchor">..</h1> or <h1 name="my-anchor">..</h1>