Why is it important to learn HTML

Answer 1

there are a lot of markup languages if u do not want to learn html there is coldfusion and many others

Answer 2

<answer>
Without HTML, you literally have no page. No content, no style, nothing. All you have is JS prompts and alerts, which makes for a very boring and plain website.
HTML makes everything more interactive, with things like buttons, images, etc. JavaScript and CSS can't handle all of that alone.
This is also why you need ALL 3 languages to have a truly great webpage.
</answer>
<note>
Unless, of course, you learn a DIFFERENT markup language. In that case, you won't even need HTML.
</note>