Why does progress element work even though there is no <DOCTYPE HTML>declaration?

Question

https://code.sololearn.com/We4CNgK019MP/?ref=app As we all know that progress element is of HTML 5, then why is this code working even thought there is no <DOCTYPE HTML> declaration? Please help me.

Answer 1

It's works because it's a html5 declaration and if there is no < !DOCKTYPE HTML> the browser will automatically choose the familiar one but it is necessary to use < !DOCKTYPE HTML> to make your webpage get displayed correctly