Is it worth learning html(5) tags in order and spending time on it separately, or is it better to practice as a problem arises?

Question

HTML

Typesetting (basic level), but I don't know all html(5) tags and attributes.
Is it worth it to learn html tags and attributes in alphabetical/categorical order (for example, how to learn English words) and spend time on this. Or better as a specific task arises.

Answer 1

The only way to learn HTML -

Answer 2

If we are talking specifically about HTML5 - understand the semantics, understand what are inline elements, block elements, and most importantly - sectioning elements. Get a basic understanding of the different HTML5 APIs.
Reading the specification with a notebook in hand in order to make notes to yourself - 1 day. You write down important points and use them as a cheat sheet. You can create a table in Excel where you can break the tags into types and indicate useful notes for each.
Learning as you go is fine. The main thing is to spend enough time on this and really learn, and not copy-paste from the network the first piece of code that comes across - it may well not be the best practice, even if it hangs on the first page of search results.
It is also useful to subscribe to rss-channels of the right sites and blogs, regularly read news and lessons. This should be a daily routine.

Answer 3

I think you should spend time and understand such a thing as semantics.

Answer 4

Must have an idea.)

Answer 5

the layout is basically div span ul ol li, sometimes it happens nav section header footer aside though rarely, the main thing is that video audio was added, there was also an auto-check of input for email correspondence.
It is not so important what elements to type up, the main thing is that it looks the same in all browsers.

Answer 6

Judging by the text of the error, the problem is in the product attributes in Magento itself, a non-existent (or deleted) attribute is attached to one of the products.