HTML Questions:

What does a doctype do?
How do you serve a page with content in multiple languages?
What kind of things must you be wary of when design or developing for multilingual sites?
What are data- attributes good for?
Consider HTML5 as an open web platform. What are the building blocks of HTML5?
Describe the difference between a cookie, sessionStorage and localStorage.
Describe the difference between <script>, <script async> and <script defer>.
Why is it generally a good idea to position CSS <link>s between <head></head> and JS <script>s just before </body>? Do you know any exceptions?
What is progressive rendering?
Why you would use a srcset attribute in an image tag? Explain the process the browser uses when evaluating the content of this attribute.
Have you used different HTML templating languages before?